[PATCHv2 0/3] perf tools: Allow to enable/disable events via control pipe

[PATCHv2 0/3] perf tools: Allow to enable/disable events via control pipe

[Jiri Olsa]

hi,
adding support to enable/disable specific events via control
file via following commands:

    # echo enable-sched:sched_process_fork > control
    # echo disabled-sched:sched_process_fork > control

v2 changes:
  - added acks
  - change list to evlist [Arnaldo]
  - add evlist-verbose command [Arnaldo]
  - add '' to enale-/disable- error message

The code is available in here:
  git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
  perf/control

thanks,
jirka


---
Jiri Olsa (3):
      perf tools: Add evlist__disable_evsel/evlist__enable_evsel
      perf tools: Allow to enable/disable events via control file
      perf tools: Add evlist/evlist-verbose control commands

 tools/perf/builtin-record.c |   4 ++++
 tools/perf/builtin-stat.c   |   4 ++++
 tools/perf/util/evlist.c    | 114 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----
 tools/perf/util/evlist.h    |  10 ++++++++++
 4 files changed, 128 insertions(+), 4 deletions(-)

[PATCH 1/3] perf tools: Add evlist__disable_evsel/evlist__enable_evsel

[Jiri Olsa]

Adding interface to enable/disable single event in the
evlist based on its name. It will be used later in new
control enable/disable interface.

Keeping the evlist::enabled true when one or more events
are enabled so the toggle can work properly and toggle
evlist to disabled state.

Acked-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Alexei Budankov <abudankov@huawei.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/perf/util/evlist.c | 69 ++++++++++++++++++++++++++++++++++++++--
 tools/perf/util/evlist.h |  2 ++
 2 files changed, 68 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 493819173a8e..70aff26612a9 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -370,7 +370,30 @@ bool evsel__cpu_iter_skip(struct evsel *ev, int cpu)
 	return true;
 }
 
-void evlist__disable(struct evlist *evlist)
+static int evsel__strcmp(struct evsel *pos, char *evsel_name)
+{
+	if (!evsel_name)
+		return 0;
+	if (evsel__is_dummy_event(pos))
+		return 1;
+	return strcmp(pos->name, evsel_name);
+}
+
+static int evlist__is_enabled(struct evlist *evlist)
+{
+	struct evsel *pos;
+
+	evlist__for_each_entry(evlist, pos) {
+		if (!evsel__is_group_leader(pos) || !pos->core.fd)
+			continue;
+		/* If at least one event is enabled, evlist is enabled. */
+		if (!pos->disabled)
+			return true;
+	}
+	return false;
+}
+
+static void __evlist__disable(struct evlist *evlist, char *evsel_name)
 {
 	struct evsel *pos;
 	struct affinity affinity;
@@ -386,6 +409,8 @@ void evlist__disable(struct evlist *evlist)
 			affinity__set(&affinity, cpu);
 
 			evlist__for_each_entry(evlist, pos) {
+				if (evsel__strcmp(pos, evsel_name))
+					continue;
 				if (evsel__cpu_iter_skip(pos, cpu))
 					continue;
 				if (pos->disabled || !evsel__is_group_leader(pos) || !pos->core.fd)
@@ -403,15 +428,34 @@ void evlist__disable(struct evlist *evlist)
 
 	affinity__cleanup(&affinity);
 	evlist__for_each_entry(evlist, pos) {
+		if (evsel__strcmp(pos, evsel_name))
+			continue;
 		if (!evsel__is_group_leader(pos) || !pos->core.fd)
 			continue;
 		pos->disabled = true;
 	}
 
-	evlist->enabled = false;
+	/*
+	 * If we disabled only single event, we need to check
+	 * the enabled state of the evlist manually.
+	 */
+	if (evsel_name)
+		evlist->enabled = evlist__is_enabled(evlist);
+	else
+		evlist->enabled = false;
+}
+
+void evlist__disable(struct evlist *evlist)
+{
+	__evlist__disable(evlist, NULL);
+}
+
+void evlist__disable_evsel(struct evlist *evlist, char *evsel_name)
+{
+	__evlist__disable(evlist, evsel_name);
 }
 
-void evlist__enable(struct evlist *evlist)
+static void __evlist__enable(struct evlist *evlist, char *evsel_name)
 {
 	struct evsel *pos;
 	struct affinity affinity;
@@ -424,6 +468,8 @@ void evlist__enable(struct evlist *evlist)
 		affinity__set(&affinity, cpu);
 
 		evlist__for_each_entry(evlist, pos) {
+			if (evsel__strcmp(pos, evsel_name))
+				continue;
 			if (evsel__cpu_iter_skip(pos, cpu))
 				continue;
 			if (!evsel__is_group_leader(pos) || !pos->core.fd)
@@ -433,14 +479,31 @@ void evlist__enable(struct evlist *evlist)
 	}
 	affinity__cleanup(&affinity);
 	evlist__for_each_entry(evlist, pos) {
+		if (evsel__strcmp(pos, evsel_name))
+			continue;
 		if (!evsel__is_group_leader(pos) || !pos->core.fd)
 			continue;
 		pos->disabled = false;
 	}
 
+	/*
+	 * Even single event sets the 'enabled' for evlist,
+	 * so the toggle can work properly and toggle to
+	 * 'disabled' state.
+	 */
 	evlist->enabled = true;
 }
 
+void evlist__enable(struct evlist *evlist)
+{
+	__evlist__enable(evlist, NULL);
+}
+
+void evlist__enable_evsel(struct evlist *evlist, char *evsel_name)
+{
+	__evlist__enable(evlist, evsel_name);
+}
+
 void evlist__toggle_enable(struct evlist *evlist)
 {
 	(evlist->enabled ? evlist__disable : evlist__enable)(evlist);
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index 9b0c795736bb..1aae75895dea 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -186,6 +186,8 @@ size_t evlist__mmap_size(unsigned long pages);
 void evlist__disable(struct evlist *evlist);
 void evlist__enable(struct evlist *evlist);
 void evlist__toggle_enable(struct evlist *evlist);
+void evlist__disable_evsel(struct evlist *evlist, char *evsel_name);
+void evlist__enable_evsel(struct evlist *evlist, char *evsel_name);
 
 int evlist__enable_event_idx(struct evlist *evlist, struct evsel *evsel, int idx);
 
-- 
2.26.2

[PATCH 2/3] perf tools: Allow to enable/disable events via control file

[Jiri Olsa]

Adding new control events to enable/disable specific event.
The interface string for control file are:

  'enable-<EVENT NAME>'
  'disable-<EVENT NAME>'

when received the command, perf will scan the current evlist
for <EVENT NAME> and if found it's enabled/disabled.

Example session:

  terminal 1:
    # mkfifo control ack perf.pipe
    # perf record --control=fifo:control,ack -D -1 --no-buffering -e 'sched:*' -o - > perf.pipe
    Events disabled

  terminal 2:
    # cat perf.pipe | ./perf --no-pager script -i -

  terminal 3:
    # echo enable-sched:sched_process_fork > control

  terminal 1:
    # mkfifo control ack perf.pipe
    # perf record --control=fifo:control,ack -D -1 --no-buffering -e 'sched:*' -o - > perf.pipe
    ...
    event sched:sched_process_fork enabled

  terminal 2:
    # cat perf.pipe | ./perf --no-pager script -i -
    bash 33349 [034] 149587.674295: sched:sched_process_fork: comm=bash pid=33349 child_comm=bash child_pid=34056
    bash 33349 [034] 149588.239521: sched:sched_process_fork: comm=bash pid=33349 child_comm=bash child_pid=34057

  terminal 3:
    # echo enable-sched:sched_wakeup_new > control

  terminal 1:
    # mkfifo control ack perf.pipe
    # perf record --control=fifo:control,ack -D -1 --no-buffering -e 'sched:*' -o - > perf.pipe
    ...
    event sched:sched_wakeup_new enabled

  terminal 2:
    # cat perf.pipe | ./perf --no-pager script -i -
    ...
    bash 33349 [034] 149632.228023: sched:sched_process_fork: comm=bash pid=33349 child_comm=bash child_pid=34059
    bash 33349 [034] 149632.228050:   sched:sched_wakeup_new: bash:34059 [120] success=1 CPU:036
    bash 33349 [034] 149633.950005: sched:sched_process_fork: comm=bash pid=33349 child_comm=bash child_pid=34060
    bash 33349 [034] 149633.950030:   sched:sched_wakeup_new: bash:34060 [120] success=1 CPU:036

Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/perf/builtin-record.c |  2 ++
 tools/perf/builtin-stat.c   |  2 ++
 tools/perf/util/evlist.c    | 30 +++++++++++++++++++++++++++++-
 tools/perf/util/evlist.h    |  4 ++++
 4 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index d832c108a1ca..582b8fba012c 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1949,6 +1949,8 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 				break;
 			case EVLIST_CTL_CMD_ACK:
 			case EVLIST_CTL_CMD_UNSUPPORTED:
+			case EVLIST_CTL_CMD_ENABLE_EVSEL:
+			case EVLIST_CTL_CMD_DISABLE_EVSEL:
 			default:
 				break;
 			}
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 89c32692f40c..6a21fb665008 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -590,6 +590,8 @@ static void process_evlist(struct evlist *evlist, unsigned int interval)
 		case EVLIST_CTL_CMD_SNAPSHOT:
 		case EVLIST_CTL_CMD_ACK:
 		case EVLIST_CTL_CMD_UNSUPPORTED:
+		case EVLIST_CTL_CMD_ENABLE_EVSEL:
+		case EVLIST_CTL_CMD_DISABLE_EVSEL:
 		default:
 			break;
 		}
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 70aff26612a9..729c98d10628 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1915,7 +1915,13 @@ static int evlist__ctlfd_recv(struct evlist *evlist, enum evlist_ctl_cmd *cmd,
 		 bytes_read == data_size ? "" : c == '\n' ? "\\n" : "\\0");
 
 	if (bytes_read > 0) {
-		if (!strncmp(cmd_data, EVLIST_CTL_CMD_ENABLE_TAG,
+		if (!strncmp(cmd_data, EVLIST_CTL_CMD_ENABLE_EVSEL_TAG,
+			     (sizeof(EVLIST_CTL_CMD_ENABLE_EVSEL_TAG)-1))) {
+			*cmd = EVLIST_CTL_CMD_ENABLE_EVSEL;
+		} else if (!strncmp(cmd_data, EVLIST_CTL_CMD_DISABLE_EVSEL_TAG,
+				    (sizeof(EVLIST_CTL_CMD_DISABLE_EVSEL_TAG)-1))) {
+			*cmd = EVLIST_CTL_CMD_DISABLE_EVSEL;
+		} else if (!strncmp(cmd_data, EVLIST_CTL_CMD_ENABLE_TAG,
 			     (sizeof(EVLIST_CTL_CMD_ENABLE_TAG)-1))) {
 			*cmd = EVLIST_CTL_CMD_ENABLE;
 		} else if (!strncmp(cmd_data, EVLIST_CTL_CMD_DISABLE_TAG,
@@ -1952,6 +1958,8 @@ int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
 	char cmd_data[EVLIST_CTL_CMD_MAX_LEN];
 	int ctlfd_pos = evlist->ctl_fd.pos;
 	struct pollfd *entries = evlist->core.pollfd.entries;
+	struct evsel *evsel;
+	char *evsel_name;
 
 	if (!evlist__ctlfd_initialized(evlist) || !entries[ctlfd_pos].revents)
 		return 0;
@@ -1967,6 +1975,26 @@ int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
 			case EVLIST_CTL_CMD_DISABLE:
 				evlist__disable(evlist);
 				break;
+			case EVLIST_CTL_CMD_ENABLE_EVSEL:
+				evsel_name = cmd_data + sizeof(EVLIST_CTL_CMD_ENABLE_EVSEL_TAG) - 1;
+				evsel = evlist__find_evsel_by_str(evlist, evsel_name);
+				if (evsel) {
+					evlist__enable_evsel(evlist, evsel_name);
+					pr_info("event %s enabled\n", evsel->name);
+				} else {
+					pr_info("failed: can't find '%s' event\n", evsel_name);
+				}
+				break;
+			case EVLIST_CTL_CMD_DISABLE_EVSEL:
+				evsel_name = cmd_data + sizeof(EVLIST_CTL_CMD_DISABLE_EVSEL_TAG) - 1;
+				evsel = evlist__find_evsel_by_str(evlist, evsel_name);
+				if (evsel) {
+					evlist__disable_evsel(evlist, evsel_name);
+					pr_info("event %s disabled\n", evsel->name);
+				} else {
+					pr_info("failed: can't find '%s' event\n", evsel_name);
+				}
+				break;
 			case EVLIST_CTL_CMD_SNAPSHOT:
 				break;
 			case EVLIST_CTL_CMD_ACK:
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index 1aae75895dea..e4e8ff8831a3 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -330,6 +330,8 @@ struct evsel *evlist__reset_weak_group(struct evlist *evlist, struct evsel *evse
 #define EVLIST_CTL_CMD_DISABLE_TAG "disable"
 #define EVLIST_CTL_CMD_ACK_TAG     "ack\n"
 #define EVLIST_CTL_CMD_SNAPSHOT_TAG "snapshot"
+#define EVLIST_CTL_CMD_ENABLE_EVSEL_TAG "enable-"
+#define EVLIST_CTL_CMD_DISABLE_EVSEL_TAG "disable-"
 
 #define EVLIST_CTL_CMD_MAX_LEN 64
 
@@ -337,6 +339,8 @@ enum evlist_ctl_cmd {
 	EVLIST_CTL_CMD_UNSUPPORTED = 0,
 	EVLIST_CTL_CMD_ENABLE,
 	EVLIST_CTL_CMD_DISABLE,
+	EVLIST_CTL_CMD_ENABLE_EVSEL,
+	EVLIST_CTL_CMD_DISABLE_EVSEL,
 	EVLIST_CTL_CMD_ACK,
 	EVLIST_CTL_CMD_SNAPSHOT,
 };
-- 
2.26.2

[PATCH 3/3] perf tools: Add evlist/evlist-verbose control commands

[Jiri Olsa]

Adding new control events to display all evlist events.

The interface string for control file is 'evlist' and
'evlist-verbose'.

When evlist is received, perf will scan and print current
evlist into perf record terminal.

When evlist-verbose is received perf will scan and print
current evlist details (like perf evlist -v) into perf
record terminal.

Example session:

  terminal 1:
    # mkfifo control ack perf.pipe
    # perf record --control=fifo:control,ack -e 'sched:*'

  terminal 2:
    # echo evlist > control

  terminal 1:
    # perf record --control=fifo:control,ack -e 'sched:*'
    ...
    sched:sched_kthread_stop
    sched:sched_kthread_stop_ret
    sched:sched_waking
    sched:sched_wakeup
    sched:sched_wakeup_new
    sched:sched_switch
    sched:sched_migrate_task
    sched:sched_process_free
    sched:sched_process_exit
    ...

  terminal 2:
    # echo evlist-vebose > control

  terminal 1:
    ...
    sched:sched_kthread_stop: type: 2, size: 120, config: 0x145,      \
    { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU   \
    |PERIOD|RAW|IDENTIFIER, read_format: ID, disabled: 1, inherit:    \
    1, sample_id_all: 1, exclude_guest: 1
    sched:sched_kthread_stop_ret: type: 2, size: 120, config: 0x144   \
    , { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU \
    |PERIOD|RAW|IDENTIFIER, read_format: ID, disabled: 1, inherit: 1, \
    sample_id_all: 1, exclude_guest: 1
    ...

This new evlist command is handy to get real event names when
wildcards are used.

The evlist-verbose is handy to check on actually enabled perf_event_attr
values.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/perf/builtin-record.c |  2 ++
 tools/perf/builtin-stat.c   |  2 ++
 tools/perf/util/evlist.c    | 15 +++++++++++++++
 tools/perf/util/evlist.h    |  4 ++++
 4 files changed, 23 insertions(+)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 582b8fba012c..d40406880722 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1951,6 +1951,8 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 			case EVLIST_CTL_CMD_UNSUPPORTED:
 			case EVLIST_CTL_CMD_ENABLE_EVSEL:
 			case EVLIST_CTL_CMD_DISABLE_EVSEL:
+			case EVLIST_CTL_CMD_EVLIST:
+			case EVLIST_CTL_CMD_EVLIST_VERBOSE:
 			default:
 				break;
 			}
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 6a21fb665008..425e2a8ebde6 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -592,6 +592,8 @@ static void process_evlist(struct evlist *evlist, unsigned int interval)
 		case EVLIST_CTL_CMD_UNSUPPORTED:
 		case EVLIST_CTL_CMD_ENABLE_EVSEL:
 		case EVLIST_CTL_CMD_DISABLE_EVSEL:
+		case EVLIST_CTL_CMD_EVLIST:
+		case EVLIST_CTL_CMD_EVLIST_VERBOSE:
 		default:
 			break;
 		}
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 729c98d10628..571d2ad61f4a 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -24,6 +24,7 @@
 #include "bpf-event.h"
 #include "util/string2.h"
 #include "util/perf_api_probe.h"
+#include "util/evsel_fprintf.h"
 #include <signal.h>
 #include <unistd.h>
 #include <sched.h>
@@ -1931,6 +1932,12 @@ static int evlist__ctlfd_recv(struct evlist *evlist, enum evlist_ctl_cmd *cmd,
 				    (sizeof(EVLIST_CTL_CMD_SNAPSHOT_TAG)-1))) {
 			*cmd = EVLIST_CTL_CMD_SNAPSHOT;
 			pr_debug("is snapshot\n");
+		} else if (!strncmp(cmd_data, EVLIST_CTL_CMD_EVLIST_VERBOSE_TAG,
+				    (sizeof(EVLIST_CTL_CMD_EVLIST_VERBOSE_TAG)-1))) {
+			*cmd = EVLIST_CTL_CMD_EVLIST_VERBOSE;
+		} else if (!strncmp(cmd_data, EVLIST_CTL_CMD_EVLIST_TAG,
+				    (sizeof(EVLIST_CTL_CMD_EVLIST_TAG)-1))) {
+			*cmd = EVLIST_CTL_CMD_EVLIST;
 		}
 	}
 
@@ -1954,6 +1961,7 @@ int evlist__ctlfd_ack(struct evlist *evlist)
 
 int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
 {
+	struct perf_attr_details details = { .verbose = false, };
 	int err = 0;
 	char cmd_data[EVLIST_CTL_CMD_MAX_LEN];
 	int ctlfd_pos = evlist->ctl_fd.pos;
@@ -1995,6 +2003,13 @@ int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
 					pr_info("failed: can't find '%s' event\n", evsel_name);
 				}
 				break;
+			case EVLIST_CTL_CMD_EVLIST_VERBOSE:
+				details.verbose = true;
+				__fallthrough;
+			case EVLIST_CTL_CMD_EVLIST:
+				evlist__for_each_entry(evlist, evsel)
+					evsel__fprintf(evsel, &details, stderr);
+				break;
 			case EVLIST_CTL_CMD_SNAPSHOT:
 				break;
 			case EVLIST_CTL_CMD_ACK:
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index e4e8ff8831a3..7892f084632d 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -332,6 +332,8 @@ struct evsel *evlist__reset_weak_group(struct evlist *evlist, struct evsel *evse
 #define EVLIST_CTL_CMD_SNAPSHOT_TAG "snapshot"
 #define EVLIST_CTL_CMD_ENABLE_EVSEL_TAG "enable-"
 #define EVLIST_CTL_CMD_DISABLE_EVSEL_TAG "disable-"
+#define EVLIST_CTL_CMD_EVLIST_TAG "evlist"
+#define EVLIST_CTL_CMD_EVLIST_VERBOSE_TAG "evlist-verbose"
 
 #define EVLIST_CTL_CMD_MAX_LEN 64
 
@@ -343,6 +345,8 @@ enum evlist_ctl_cmd {
 	EVLIST_CTL_CMD_DISABLE_EVSEL,
 	EVLIST_CTL_CMD_ACK,
 	EVLIST_CTL_CMD_SNAPSHOT,
+	EVLIST_CTL_CMD_EVLIST,
+	EVLIST_CTL_CMD_EVLIST_VERBOSE,
 };
 
 int evlist__parse_control(const char *str, int *ctl_fd, int *ctl_fd_ack, bool *ctl_fd_close);
-- 
2.26.2

Re: [PATCH 3/3] perf tools: Add evlist/evlist-verbose control commands

[Namhyung Kim]

Hi Jiri,

On Fri, Dec 11, 2020 at 5:43 AM Jiri Olsa <jolsa@kernel.org> wrote:
>
> Adding new control events to display all evlist events.
>
> The interface string for control file is 'evlist' and
> 'evlist-verbose'.
>
> When evlist is received, perf will scan and print current
> evlist into perf record terminal.
>
> When evlist-verbose is received perf will scan and print
> current evlist details (like perf evlist -v) into perf
> record terminal.
>
> Example session:
>
>   terminal 1:
>     # mkfifo control ack perf.pipe
>     # perf record --control=fifo:control,ack -e 'sched:*'
>
>   terminal 2:
>     # echo evlist > control
>
>   terminal 1:
>     # perf record --control=fifo:control,ack -e 'sched:*'
>     ...
>     sched:sched_kthread_stop
>     sched:sched_kthread_stop_ret
>     sched:sched_waking
>     sched:sched_wakeup
>     sched:sched_wakeup_new
>     sched:sched_switch
>     sched:sched_migrate_task
>     sched:sched_process_free
>     sched:sched_process_exit
>     ...
>
>   terminal 2:
>     # echo evlist-vebose > control
>
>   terminal 1:
>     ...
>     sched:sched_kthread_stop: type: 2, size: 120, config: 0x145,      \
>     { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU   \
>     |PERIOD|RAW|IDENTIFIER, read_format: ID, disabled: 1, inherit:    \
>     1, sample_id_all: 1, exclude_guest: 1
>     sched:sched_kthread_stop_ret: type: 2, size: 120, config: 0x144   \
>     , { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU \
>     |PERIOD|RAW|IDENTIFIER, read_format: ID, disabled: 1, inherit: 1, \
>     sample_id_all: 1, exclude_guest: 1
>     ...
>
> This new evlist command is handy to get real event names when
> wildcards are used.
>
> The evlist-verbose is handy to check on actually enabled perf_event_attr
> values.
>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>

Acked-by: Namhyung Kim <namhyung@kernel.org>

Thanks,
Namhyung


> ---
>  tools/perf/builtin-record.c |  2 ++
>  tools/perf/builtin-stat.c   |  2 ++
>  tools/perf/util/evlist.c    | 15 +++++++++++++++
>  tools/perf/util/evlist.h    |  4 ++++
>  4 files changed, 23 insertions(+)
>
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 582b8fba012c..d40406880722 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -1951,6 +1951,8 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>                         case EVLIST_CTL_CMD_UNSUPPORTED:
>                         case EVLIST_CTL_CMD_ENABLE_EVSEL:
>                         case EVLIST_CTL_CMD_DISABLE_EVSEL:
> +                       case EVLIST_CTL_CMD_EVLIST:
> +                       case EVLIST_CTL_CMD_EVLIST_VERBOSE:
>                         default:
>                                 break;
>                         }
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index 6a21fb665008..425e2a8ebde6 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -592,6 +592,8 @@ static void process_evlist(struct evlist *evlist, unsigned int interval)
>                 case EVLIST_CTL_CMD_UNSUPPORTED:
>                 case EVLIST_CTL_CMD_ENABLE_EVSEL:
>                 case EVLIST_CTL_CMD_DISABLE_EVSEL:
> +               case EVLIST_CTL_CMD_EVLIST:
> +               case EVLIST_CTL_CMD_EVLIST_VERBOSE:
>                 default:
>                         break;
>                 }
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index 729c98d10628..571d2ad61f4a 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -24,6 +24,7 @@
>  #include "bpf-event.h"
>  #include "util/string2.h"
>  #include "util/perf_api_probe.h"
> +#include "util/evsel_fprintf.h"
>  #include <signal.h>
>  #include <unistd.h>
>  #include <sched.h>
> @@ -1931,6 +1932,12 @@ static int evlist__ctlfd_recv(struct evlist *evlist, enum evlist_ctl_cmd *cmd,
>                                     (sizeof(EVLIST_CTL_CMD_SNAPSHOT_TAG)-1))) {
>                         *cmd = EVLIST_CTL_CMD_SNAPSHOT;
>                         pr_debug("is snapshot\n");
> +               } else if (!strncmp(cmd_data, EVLIST_CTL_CMD_EVLIST_VERBOSE_TAG,
> +                                   (sizeof(EVLIST_CTL_CMD_EVLIST_VERBOSE_TAG)-1))) {
> +                       *cmd = EVLIST_CTL_CMD_EVLIST_VERBOSE;
> +               } else if (!strncmp(cmd_data, EVLIST_CTL_CMD_EVLIST_TAG,
> +                                   (sizeof(EVLIST_CTL_CMD_EVLIST_TAG)-1))) {
> +                       *cmd = EVLIST_CTL_CMD_EVLIST;
>                 }
>         }
>
> @@ -1954,6 +1961,7 @@ int evlist__ctlfd_ack(struct evlist *evlist)
>
>  int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
>  {
> +       struct perf_attr_details details = { .verbose = false, };
>         int err = 0;
>         char cmd_data[EVLIST_CTL_CMD_MAX_LEN];
>         int ctlfd_pos = evlist->ctl_fd.pos;
> @@ -1995,6 +2003,13 @@ int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
>                                         pr_info("failed: can't find '%s' event\n", evsel_name);
>                                 }
>                                 break;
> +                       case EVLIST_CTL_CMD_EVLIST_VERBOSE:
> +                               details.verbose = true;
> +                               __fallthrough;
> +                       case EVLIST_CTL_CMD_EVLIST:
> +                               evlist__for_each_entry(evlist, evsel)
> +                                       evsel__fprintf(evsel, &details, stderr);
> +                               break;
>                         case EVLIST_CTL_CMD_SNAPSHOT:
>                                 break;
>                         case EVLIST_CTL_CMD_ACK:
> diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
> index e4e8ff8831a3..7892f084632d 100644
> --- a/tools/perf/util/evlist.h
> +++ b/tools/perf/util/evlist.h
> @@ -332,6 +332,8 @@ struct evsel *evlist__reset_weak_group(struct evlist *evlist, struct evsel *evse
>  #define EVLIST_CTL_CMD_SNAPSHOT_TAG "snapshot"
>  #define EVLIST_CTL_CMD_ENABLE_EVSEL_TAG "enable-"
>  #define EVLIST_CTL_CMD_DISABLE_EVSEL_TAG "disable-"
> +#define EVLIST_CTL_CMD_EVLIST_TAG "evlist"
> +#define EVLIST_CTL_CMD_EVLIST_VERBOSE_TAG "evlist-verbose"
>
>  #define EVLIST_CTL_CMD_MAX_LEN 64
>
> @@ -343,6 +345,8 @@ enum evlist_ctl_cmd {
>         EVLIST_CTL_CMD_DISABLE_EVSEL,
>         EVLIST_CTL_CMD_ACK,
>         EVLIST_CTL_CMD_SNAPSHOT,
> +       EVLIST_CTL_CMD_EVLIST,
> +       EVLIST_CTL_CMD_EVLIST_VERBOSE,
>  };
>
>  int evlist__parse_control(const char *str, int *ctl_fd, int *ctl_fd_ack, bool *ctl_fd_close);
> --
> 2.26.2
>

Re: [PATCH 2/3] perf tools: Allow to enable/disable events via control file

[Arnaldo Carvalho de Melo]

Em Thu, Dec 10, 2020 at 09:43:29PM +0100, Jiri Olsa escreveu:
> Adding new control events to enable/disable specific event.
> The interface string for control file are:
> 
>   'enable-<EVENT NAME>'
>   'disable-<EVENT NAME>'

Wwy do we have "enable-" as the "tag" for this?

Also is it possible to use "enable sched:*" and have that match what is
in the evlist and enable (or disable, if using "disable sched:*") what
matches?

This second suggestion can be done on top of this, i.e. as an
enhancement, but mixing up the command (enable, disable) with its
arguments looks strange.

- Arnaldo
 
> when received the command, perf will scan the current evlist
> for <EVENT NAME> and if found it's enabled/disabled.
> 
> Example session:
> 
>   terminal 1:
>     # mkfifo control ack perf.pipe
>     # perf record --control=fifo:control,ack -D -1 --no-buffering -e 'sched:*' -o - > perf.pipe
>     Events disabled
> 
>   terminal 2:
>     # cat perf.pipe | ./perf --no-pager script -i -
> 
>   terminal 3:
>     # echo enable-sched:sched_process_fork > control
> 
>   terminal 1:
>     # mkfifo control ack perf.pipe
>     # perf record --control=fifo:control,ack -D -1 --no-buffering -e 'sched:*' -o - > perf.pipe
>     ...
>     event sched:sched_process_fork enabled
> 
>   terminal 2:
>     # cat perf.pipe | ./perf --no-pager script -i -
>     bash 33349 [034] 149587.674295: sched:sched_process_fork: comm=bash pid=33349 child_comm=bash child_pid=34056
>     bash 33349 [034] 149588.239521: sched:sched_process_fork: comm=bash pid=33349 child_comm=bash child_pid=34057
> 
>   terminal 3:
>     # echo enable-sched:sched_wakeup_new > control
> 
>   terminal 1:
>     # mkfifo control ack perf.pipe
>     # perf record --control=fifo:control,ack -D -1 --no-buffering -e 'sched:*' -o - > perf.pipe
>     ...
>     event sched:sched_wakeup_new enabled
> 
>   terminal 2:
>     # cat perf.pipe | ./perf --no-pager script -i -
>     ...
>     bash 33349 [034] 149632.228023: sched:sched_process_fork: comm=bash pid=33349 child_comm=bash child_pid=34059
>     bash 33349 [034] 149632.228050:   sched:sched_wakeup_new: bash:34059 [120] success=1 CPU:036
>     bash 33349 [034] 149633.950005: sched:sched_process_fork: comm=bash pid=33349 child_comm=bash child_pid=34060
>     bash 33349 [034] 149633.950030:   sched:sched_wakeup_new: bash:34060 [120] success=1 CPU:036
> 
> Acked-by: Namhyung Kim <namhyung@kernel.org>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
>  tools/perf/builtin-record.c |  2 ++
>  tools/perf/builtin-stat.c   |  2 ++
>  tools/perf/util/evlist.c    | 30 +++++++++++++++++++++++++++++-
>  tools/perf/util/evlist.h    |  4 ++++
>  4 files changed, 37 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index d832c108a1ca..582b8fba012c 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -1949,6 +1949,8 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>  				break;
>  			case EVLIST_CTL_CMD_ACK:
>  			case EVLIST_CTL_CMD_UNSUPPORTED:
> +			case EVLIST_CTL_CMD_ENABLE_EVSEL:
> +			case EVLIST_CTL_CMD_DISABLE_EVSEL:
>  			default:
>  				break;
>  			}
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index 89c32692f40c..6a21fb665008 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -590,6 +590,8 @@ static void process_evlist(struct evlist *evlist, unsigned int interval)
>  		case EVLIST_CTL_CMD_SNAPSHOT:
>  		case EVLIST_CTL_CMD_ACK:
>  		case EVLIST_CTL_CMD_UNSUPPORTED:
> +		case EVLIST_CTL_CMD_ENABLE_EVSEL:
> +		case EVLIST_CTL_CMD_DISABLE_EVSEL:
>  		default:
>  			break;
>  		}
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index 70aff26612a9..729c98d10628 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -1915,7 +1915,13 @@ static int evlist__ctlfd_recv(struct evlist *evlist, enum evlist_ctl_cmd *cmd,
>  		 bytes_read == data_size ? "" : c == '\n' ? "\\n" : "\\0");
>  
>  	if (bytes_read > 0) {
> -		if (!strncmp(cmd_data, EVLIST_CTL_CMD_ENABLE_TAG,
> +		if (!strncmp(cmd_data, EVLIST_CTL_CMD_ENABLE_EVSEL_TAG,
> +			     (sizeof(EVLIST_CTL_CMD_ENABLE_EVSEL_TAG)-1))) {
> +			*cmd = EVLIST_CTL_CMD_ENABLE_EVSEL;
> +		} else if (!strncmp(cmd_data, EVLIST_CTL_CMD_DISABLE_EVSEL_TAG,
> +				    (sizeof(EVLIST_CTL_CMD_DISABLE_EVSEL_TAG)-1))) {
> +			*cmd = EVLIST_CTL_CMD_DISABLE_EVSEL;
> +		} else if (!strncmp(cmd_data, EVLIST_CTL_CMD_ENABLE_TAG,
>  			     (sizeof(EVLIST_CTL_CMD_ENABLE_TAG)-1))) {
>  			*cmd = EVLIST_CTL_CMD_ENABLE;
>  		} else if (!strncmp(cmd_data, EVLIST_CTL_CMD_DISABLE_TAG,
> @@ -1952,6 +1958,8 @@ int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
>  	char cmd_data[EVLIST_CTL_CMD_MAX_LEN];
>  	int ctlfd_pos = evlist->ctl_fd.pos;
>  	struct pollfd *entries = evlist->core.pollfd.entries;
> +	struct evsel *evsel;
> +	char *evsel_name;
>  
>  	if (!evlist__ctlfd_initialized(evlist) || !entries[ctlfd_pos].revents)
>  		return 0;
> @@ -1967,6 +1975,26 @@ int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
>  			case EVLIST_CTL_CMD_DISABLE:
>  				evlist__disable(evlist);
>  				break;
> +			case EVLIST_CTL_CMD_ENABLE_EVSEL:
> +				evsel_name = cmd_data + sizeof(EVLIST_CTL_CMD_ENABLE_EVSEL_TAG) - 1;
> +				evsel = evlist__find_evsel_by_str(evlist, evsel_name);
> +				if (evsel) {
> +					evlist__enable_evsel(evlist, evsel_name);
> +					pr_info("event %s enabled\n", evsel->name);
> +				} else {
> +					pr_info("failed: can't find '%s' event\n", evsel_name);
> +				}
> +				break;
> +			case EVLIST_CTL_CMD_DISABLE_EVSEL:
> +				evsel_name = cmd_data + sizeof(EVLIST_CTL_CMD_DISABLE_EVSEL_TAG) - 1;
> +				evsel = evlist__find_evsel_by_str(evlist, evsel_name);
> +				if (evsel) {
> +					evlist__disable_evsel(evlist, evsel_name);
> +					pr_info("event %s disabled\n", evsel->name);
> +				} else {
> +					pr_info("failed: can't find '%s' event\n", evsel_name);
> +				}
> +				break;
>  			case EVLIST_CTL_CMD_SNAPSHOT:
>  				break;
>  			case EVLIST_CTL_CMD_ACK:
> diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
> index 1aae75895dea..e4e8ff8831a3 100644
> --- a/tools/perf/util/evlist.h
> +++ b/tools/perf/util/evlist.h
> @@ -330,6 +330,8 @@ struct evsel *evlist__reset_weak_group(struct evlist *evlist, struct evsel *evse
>  #define EVLIST_CTL_CMD_DISABLE_TAG "disable"
>  #define EVLIST_CTL_CMD_ACK_TAG     "ack\n"
>  #define EVLIST_CTL_CMD_SNAPSHOT_TAG "snapshot"
> +#define EVLIST_CTL_CMD_ENABLE_EVSEL_TAG "enable-"
> +#define EVLIST_CTL_CMD_DISABLE_EVSEL_TAG "disable-"
>  
>  #define EVLIST_CTL_CMD_MAX_LEN 64
>  
> @@ -337,6 +339,8 @@ enum evlist_ctl_cmd {
>  	EVLIST_CTL_CMD_UNSUPPORTED = 0,
>  	EVLIST_CTL_CMD_ENABLE,
>  	EVLIST_CTL_CMD_DISABLE,
> +	EVLIST_CTL_CMD_ENABLE_EVSEL,
> +	EVLIST_CTL_CMD_DISABLE_EVSEL,
>  	EVLIST_CTL_CMD_ACK,
>  	EVLIST_CTL_CMD_SNAPSHOT,
>  };
> -- 
> 2.26.2
> 

-- 

- Arnaldo

Re: [PATCH 1/3] perf tools: Add evlist__disable_evsel/evlist__enable_evsel

[Arnaldo Carvalho de Melo]

Em Thu, Dec 10, 2020 at 09:43:28PM +0100, Jiri Olsa escreveu:
> Adding interface to enable/disable single event in the
> evlist based on its name. It will be used later in new
> control enable/disable interface.
> 
> Keeping the evlist::enabled true when one or more events
> are enabled so the toggle can work properly and toggle
> evlist to disabled state.


Thanks, applied.

- Arnaldo

 
> Acked-by: Namhyung Kim <namhyung@kernel.org>
> Acked-by: Alexei Budankov <abudankov@huawei.com>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
>  tools/perf/util/evlist.c | 69 ++++++++++++++++++++++++++++++++++++++--
>  tools/perf/util/evlist.h |  2 ++
>  2 files changed, 68 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index 493819173a8e..70aff26612a9 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -370,7 +370,30 @@ bool evsel__cpu_iter_skip(struct evsel *ev, int cpu)
>  	return true;
>  }
>  
> -void evlist__disable(struct evlist *evlist)
> +static int evsel__strcmp(struct evsel *pos, char *evsel_name)
> +{
> +	if (!evsel_name)
> +		return 0;
> +	if (evsel__is_dummy_event(pos))
> +		return 1;
> +	return strcmp(pos->name, evsel_name);
> +}
> +
> +static int evlist__is_enabled(struct evlist *evlist)
> +{
> +	struct evsel *pos;
> +
> +	evlist__for_each_entry(evlist, pos) {
> +		if (!evsel__is_group_leader(pos) || !pos->core.fd)
> +			continue;
> +		/* If at least one event is enabled, evlist is enabled. */
> +		if (!pos->disabled)
> +			return true;
> +	}
> +	return false;
> +}
> +
> +static void __evlist__disable(struct evlist *evlist, char *evsel_name)
>  {
>  	struct evsel *pos;
>  	struct affinity affinity;
> @@ -386,6 +409,8 @@ void evlist__disable(struct evlist *evlist)
>  			affinity__set(&affinity, cpu);
>  
>  			evlist__for_each_entry(evlist, pos) {
> +				if (evsel__strcmp(pos, evsel_name))
> +					continue;
>  				if (evsel__cpu_iter_skip(pos, cpu))
>  					continue;
>  				if (pos->disabled || !evsel__is_group_leader(pos) || !pos->core.fd)
> @@ -403,15 +428,34 @@ void evlist__disable(struct evlist *evlist)
>  
>  	affinity__cleanup(&affinity);
>  	evlist__for_each_entry(evlist, pos) {
> +		if (evsel__strcmp(pos, evsel_name))
> +			continue;
>  		if (!evsel__is_group_leader(pos) || !pos->core.fd)
>  			continue;
>  		pos->disabled = true;
>  	}
>  
> -	evlist->enabled = false;
> +	/*
> +	 * If we disabled only single event, we need to check
> +	 * the enabled state of the evlist manually.
> +	 */
> +	if (evsel_name)
> +		evlist->enabled = evlist__is_enabled(evlist);
> +	else
> +		evlist->enabled = false;
> +}
> +
> +void evlist__disable(struct evlist *evlist)
> +{
> +	__evlist__disable(evlist, NULL);
> +}
> +
> +void evlist__disable_evsel(struct evlist *evlist, char *evsel_name)
> +{
> +	__evlist__disable(evlist, evsel_name);
>  }
>  
> -void evlist__enable(struct evlist *evlist)
> +static void __evlist__enable(struct evlist *evlist, char *evsel_name)
>  {
>  	struct evsel *pos;
>  	struct affinity affinity;
> @@ -424,6 +468,8 @@ void evlist__enable(struct evlist *evlist)
>  		affinity__set(&affinity, cpu);
>  
>  		evlist__for_each_entry(evlist, pos) {
> +			if (evsel__strcmp(pos, evsel_name))
> +				continue;
>  			if (evsel__cpu_iter_skip(pos, cpu))
>  				continue;
>  			if (!evsel__is_group_leader(pos) || !pos->core.fd)
> @@ -433,14 +479,31 @@ void evlist__enable(struct evlist *evlist)
>  	}
>  	affinity__cleanup(&affinity);
>  	evlist__for_each_entry(evlist, pos) {
> +		if (evsel__strcmp(pos, evsel_name))
> +			continue;
>  		if (!evsel__is_group_leader(pos) || !pos->core.fd)
>  			continue;
>  		pos->disabled = false;
>  	}
>  
> +	/*
> +	 * Even single event sets the 'enabled' for evlist,
> +	 * so the toggle can work properly and toggle to
> +	 * 'disabled' state.
> +	 */
>  	evlist->enabled = true;
>  }
>  
> +void evlist__enable(struct evlist *evlist)
> +{
> +	__evlist__enable(evlist, NULL);
> +}
> +
> +void evlist__enable_evsel(struct evlist *evlist, char *evsel_name)
> +{
> +	__evlist__enable(evlist, evsel_name);
> +}
> +
>  void evlist__toggle_enable(struct evlist *evlist)
>  {
>  	(evlist->enabled ? evlist__disable : evlist__enable)(evlist);
> diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
> index 9b0c795736bb..1aae75895dea 100644
> --- a/tools/perf/util/evlist.h
> +++ b/tools/perf/util/evlist.h
> @@ -186,6 +186,8 @@ size_t evlist__mmap_size(unsigned long pages);
>  void evlist__disable(struct evlist *evlist);
>  void evlist__enable(struct evlist *evlist);
>  void evlist__toggle_enable(struct evlist *evlist);
> +void evlist__disable_evsel(struct evlist *evlist, char *evsel_name);
> +void evlist__enable_evsel(struct evlist *evlist, char *evsel_name);
>  
>  int evlist__enable_event_idx(struct evlist *evlist, struct evsel *evsel, int idx);
>  
> -- 
> 2.26.2
> 

-- 

- Arnaldo

Re: [PATCH 3/3] perf tools: Add evlist/evlist-verbose control commands

[Arnaldo Carvalho de Melo]

Em Thu, Dec 10, 2020 at 09:43:30PM +0100, Jiri Olsa escreveu:
> Adding new control events to display all evlist events.
> 
> The interface string for control file is 'evlist' and
> 'evlist-verbose'.

Can't we pass args to such commands?

Then its just one event, i.e. "evlist", and -v can be passed to it.

i.e.:

The commands would be:

evlist

That produces:

 
   terminal 2:
     # echo evlist > control
 
   terminal 1:
     # perf record --control=fifo:control,ack -e 'sched:*'
     ...
     sched:sched_kthread_stop
     sched:sched_kthread_stop_ret
     sched:sched_waking

And 'evlist -v', that produces:

   terminal 2:
     # echo "evlist -v" > control
 
   terminal 1:
     ...
     sched:sched_kthread_stop: type: 2, size: 120, config: 0x145,      \
     { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU   \
     |PERIOD|RAW|IDENTIFIER, read_format: ID, disabled: 1, inherit:    \
     1, sample_id_all: 1, exclude_guest: 1
     sched:sched_kthread_stop_ret: type: 2, size: 120, config: 0x144   \
     , { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU \
     |PERIOD|RAW|IDENTIFIER, read_format: ID, disabled: 1, inherit: 1, \
     sample_id_all: 1, exclude_guest: 1
     ...

I think we could even change things such that we pass a file descriptor
for cmd_evlist to use, passing the argv received from the control file,
etc.

With this in place we could reuse more stuff and allow using this
control file to obtain information such as 'perf report --header-only',
etc.

echo "report --header-only" > control would get us the same thing as
'perf report --header-only' for an existing perf.data file:


# perf report --header-only
# ========
# captured on    : Tue Dec 15 12:21:23 2020
# header version : 1
# data offset    : 432
# data size      : 1648
# feat offset    : 2080
# hostname : five
# os release : 5.10.0-rc7+
# perf version : 5.10.rc6.gc56d2601b5d0
# arch : x86_64
# nrcpus online : 24
# nrcpus avail : 24
# cpudesc : AMD Ryzen 9 3900X 12-Core Processor
# cpuid : AuthenticAMD,23,113,0
# total memory : 32884432 kB
# cmdline : /home/acme/bin/perf record ls 
# event : name = cycles:u, , id = { 85540, 85541, 85542, 85543, 85544, 85545, 85546, 85547, 85548, 85549, 85550, 85551, 85552, 85553, 85554, 85555, 85556, 85557, 85558, 85559, 85560, 85561, 85562, 85563 }, size = 120, { sample_period, sample_freq } = 4000, sample_type = IP|TID|TIME|PERIOD, read_format = ID, disabled = 1, inherit = 1, exclude_kernel = 1, mmap = 1, comm = 1, freq = 1, enable_on_exec = 1, task = 1, sample_id_all = 1, exclude_guest = 1, mmap2 = 1, comm_exec = 1, ksymbol = 1, bpf_event = 1
# CPU_TOPOLOGY info available, use -I to display
# NUMA_TOPOLOGY info available, use -I to display
# pmu mappings: amd_df = 8, software = 1, ibs_op = 11, power = 14, ibs_fetch = 10, uprobe = 7, cpu = 4, amd_iommu_0 = 12, breakpoint = 5, amd_l3 = 9, tracepoint = 2, kprobe = 6, msr = 13
# CACHE info available, use -I to display
# time of first sample : 12184.494971
# time of last sample : 12184.495496
# sample duration :      0.525 ms
# MEM_TOPOLOGY info available, use -I to display
# cpu pmu capabilities: max_precise=0
# missing features: TRACING_DATA BRANCH_STACK GROUP_DESC AUXTRACE STAT CLOCKID DIR_FORMAT COMPRESSED CLOCK_DATA 
# ========
#

I.e. users would discover that using this control file is as easy as
working with perf.data files or with the pipe mode, all the three ways
of interacting with perf would use the same command interface arguments.

- Arnaldo
 
> When evlist is received, perf will scan and print current
> evlist into perf record terminal.
> 
> When evlist-verbose is received perf will scan and print
> current evlist details (like perf evlist -v) into perf
> record terminal.
> 
> Example session:
> 
>   terminal 1:
>     # mkfifo control ack perf.pipe
>     # perf record --control=fifo:control,ack -e 'sched:*'
> 
>   terminal 2:
>     # echo evlist > control
> 
>   terminal 1:
>     # perf record --control=fifo:control,ack -e 'sched:*'
>     ...
>     sched:sched_kthread_stop
>     sched:sched_kthread_stop_ret
>     sched:sched_waking
>     sched:sched_wakeup
>     sched:sched_wakeup_new
>     sched:sched_switch
>     sched:sched_migrate_task
>     sched:sched_process_free
>     sched:sched_process_exit
>     ...
> 
>   terminal 2:
>     # echo evlist-vebose > control
> 
>   terminal 1:
>     ...
>     sched:sched_kthread_stop: type: 2, size: 120, config: 0x145,      \
>     { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU   \
>     |PERIOD|RAW|IDENTIFIER, read_format: ID, disabled: 1, inherit:    \
>     1, sample_id_all: 1, exclude_guest: 1
>     sched:sched_kthread_stop_ret: type: 2, size: 120, config: 0x144   \
>     , { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU \
>     |PERIOD|RAW|IDENTIFIER, read_format: ID, disabled: 1, inherit: 1, \
>     sample_id_all: 1, exclude_guest: 1
>     ...
> 
> This new evlist command is handy to get real event names when
> wildcards are used.
> 
> The evlist-verbose is handy to check on actually enabled perf_event_attr
> values.
> 
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
>  tools/perf/builtin-record.c |  2 ++
>  tools/perf/builtin-stat.c   |  2 ++
>  tools/perf/util/evlist.c    | 15 +++++++++++++++
>  tools/perf/util/evlist.h    |  4 ++++
>  4 files changed, 23 insertions(+)
> 
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 582b8fba012c..d40406880722 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -1951,6 +1951,8 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>  			case EVLIST_CTL_CMD_UNSUPPORTED:
>  			case EVLIST_CTL_CMD_ENABLE_EVSEL:
>  			case EVLIST_CTL_CMD_DISABLE_EVSEL:
> +			case EVLIST_CTL_CMD_EVLIST:
> +			case EVLIST_CTL_CMD_EVLIST_VERBOSE:
>  			default:
>  				break;
>  			}
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index 6a21fb665008..425e2a8ebde6 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -592,6 +592,8 @@ static void process_evlist(struct evlist *evlist, unsigned int interval)
>  		case EVLIST_CTL_CMD_UNSUPPORTED:
>  		case EVLIST_CTL_CMD_ENABLE_EVSEL:
>  		case EVLIST_CTL_CMD_DISABLE_EVSEL:
> +		case EVLIST_CTL_CMD_EVLIST:
> +		case EVLIST_CTL_CMD_EVLIST_VERBOSE:
>  		default:
>  			break;
>  		}
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index 729c98d10628..571d2ad61f4a 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -24,6 +24,7 @@
>  #include "bpf-event.h"
>  #include "util/string2.h"
>  #include "util/perf_api_probe.h"
> +#include "util/evsel_fprintf.h"
>  #include <signal.h>
>  #include <unistd.h>
>  #include <sched.h>
> @@ -1931,6 +1932,12 @@ static int evlist__ctlfd_recv(struct evlist *evlist, enum evlist_ctl_cmd *cmd,
>  				    (sizeof(EVLIST_CTL_CMD_SNAPSHOT_TAG)-1))) {
>  			*cmd = EVLIST_CTL_CMD_SNAPSHOT;
>  			pr_debug("is snapshot\n");
> +		} else if (!strncmp(cmd_data, EVLIST_CTL_CMD_EVLIST_VERBOSE_TAG,
> +				    (sizeof(EVLIST_CTL_CMD_EVLIST_VERBOSE_TAG)-1))) {
> +			*cmd = EVLIST_CTL_CMD_EVLIST_VERBOSE;
> +		} else if (!strncmp(cmd_data, EVLIST_CTL_CMD_EVLIST_TAG,
> +				    (sizeof(EVLIST_CTL_CMD_EVLIST_TAG)-1))) {
> +			*cmd = EVLIST_CTL_CMD_EVLIST;
>  		}
>  	}
>  
> @@ -1954,6 +1961,7 @@ int evlist__ctlfd_ack(struct evlist *evlist)
>  
>  int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
>  {
> +	struct perf_attr_details details = { .verbose = false, };
>  	int err = 0;
>  	char cmd_data[EVLIST_CTL_CMD_MAX_LEN];
>  	int ctlfd_pos = evlist->ctl_fd.pos;
> @@ -1995,6 +2003,13 @@ int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
>  					pr_info("failed: can't find '%s' event\n", evsel_name);
>  				}
>  				break;
> +			case EVLIST_CTL_CMD_EVLIST_VERBOSE:
> +				details.verbose = true;
> +				__fallthrough;
> +			case EVLIST_CTL_CMD_EVLIST:
> +				evlist__for_each_entry(evlist, evsel)
> +					evsel__fprintf(evsel, &details, stderr);
> +				break;
>  			case EVLIST_CTL_CMD_SNAPSHOT:
>  				break;
>  			case EVLIST_CTL_CMD_ACK:
> diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
> index e4e8ff8831a3..7892f084632d 100644
> --- a/tools/perf/util/evlist.h
> +++ b/tools/perf/util/evlist.h
> @@ -332,6 +332,8 @@ struct evsel *evlist__reset_weak_group(struct evlist *evlist, struct evsel *evse
>  #define EVLIST_CTL_CMD_SNAPSHOT_TAG "snapshot"
>  #define EVLIST_CTL_CMD_ENABLE_EVSEL_TAG "enable-"
>  #define EVLIST_CTL_CMD_DISABLE_EVSEL_TAG "disable-"
> +#define EVLIST_CTL_CMD_EVLIST_TAG "evlist"
> +#define EVLIST_CTL_CMD_EVLIST_VERBOSE_TAG "evlist-verbose"
>  
>  #define EVLIST_CTL_CMD_MAX_LEN 64
>  
> @@ -343,6 +345,8 @@ enum evlist_ctl_cmd {
>  	EVLIST_CTL_CMD_DISABLE_EVSEL,
>  	EVLIST_CTL_CMD_ACK,
>  	EVLIST_CTL_CMD_SNAPSHOT,
> +	EVLIST_CTL_CMD_EVLIST,
> +	EVLIST_CTL_CMD_EVLIST_VERBOSE,
>  };
>  
>  int evlist__parse_control(const char *str, int *ctl_fd, int *ctl_fd_ack, bool *ctl_fd_close);
> -- 
> 2.26.2
> 

-- 

- Arnaldo

Re: [PATCH 2/3] perf tools: Allow to enable/disable events via control file

[Jiri Olsa]

On Tue, Dec 15, 2020 at 12:14:13PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Thu, Dec 10, 2020 at 09:43:29PM +0100, Jiri Olsa escreveu:
> > Adding new control events to enable/disable specific event.
> > The interface string for control file are:
> > 
> >   'enable-<EVENT NAME>'
> >   'disable-<EVENT NAME>'
> 
> Wwy do we have "enable-" as the "tag" for this?

the whole 'enable-' is prefix for command that enables specific event
following '-' starts the event name

> 
> Also is it possible to use "enable sched:*" and have that match what is
> in the evlist and enable (or disable, if using "disable sched:*") what
> matches?

yep, that should be possible to add

> 
> This second suggestion can be done on top of this, i.e. as an
> enhancement, but mixing up the command (enable, disable) with its
> arguments looks strange.

the '-' determines that there's event name following,
pure 'enable' switches on everything

jirka

Re: [PATCH 3/3] perf tools: Add evlist/evlist-verbose control commands

[Jiri Olsa]

On Tue, Dec 15, 2020 at 12:23:43PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Thu, Dec 10, 2020 at 09:43:30PM +0100, Jiri Olsa escreveu:
> > Adding new control events to display all evlist events.
> > 
> > The interface string for control file is 'evlist' and
> > 'evlist-verbose'.
> 
> Can't we pass args to such commands?
> 
> Then its just one event, i.e. "evlist", and -v can be passed to it.

it's possible but it adds another processing to the single record thread
where we want to be fast

but I agree it could be helpful to get the other output that evsel__fprintf
can print, and we already call evsel__fprintf, so it's just a matter of
setting 'struct perf_attr_details' properly

I need to check, but perhaps we could use ' ' instead of '-' and have:

  echo 'evlist -v' > control
  echo 'evlist -g' > control
  echo 'evlist -F' > control

and have:

  echo 'enable cycles' > control

instead of:

  echo 'enable-cycles' > control

I'd like to avoid any elaborate parsing logic..

how about that?

> 
> i.e.:
> 
> The commands would be:
> 
> evlist
> 
> That produces:
> 
>  
>    terminal 2:
>      # echo evlist > control
>  
>    terminal 1:
>      # perf record --control=fifo:control,ack -e 'sched:*'
>      ...
>      sched:sched_kthread_stop
>      sched:sched_kthread_stop_ret
>      sched:sched_waking
> 
> And 'evlist -v', that produces:
> 
>    terminal 2:
>      # echo "evlist -v" > control
>  
>    terminal 1:
>      ...
>      sched:sched_kthread_stop: type: 2, size: 120, config: 0x145,      \
>      { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU   \
>      |PERIOD|RAW|IDENTIFIER, read_format: ID, disabled: 1, inherit:    \
>      1, sample_id_all: 1, exclude_guest: 1
>      sched:sched_kthread_stop_ret: type: 2, size: 120, config: 0x144   \
>      , { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU \
>      |PERIOD|RAW|IDENTIFIER, read_format: ID, disabled: 1, inherit: 1, \
>      sample_id_all: 1, exclude_guest: 1
>      ...
> 
> I think we could even change things such that we pass a file descriptor
> for cmd_evlist to use, passing the argv received from the control file,
> etc.

hum, so perf evlist opens/reads perf.data, which we do not have ready
at that point in perf record

> 
> With this in place we could reuse more stuff and allow using this
> control file to obtain information such as 'perf report --header-only',
> etc.
> 
> echo "report --header-only" > control would get us the same thing as
> 'perf report --header-only' for an existing perf.data file:

all those header data are written when record is exiting or dumped
for switch output, so we don't have that data at that moment control
command is received

> 
> 
> # perf report --header-only
> # ========
> # captured on    : Tue Dec 15 12:21:23 2020
> # header version : 1
> # data offset    : 432
> # data size      : 1648
> # feat offset    : 2080
> # hostname : five
> # os release : 5.10.0-rc7+
> # perf version : 5.10.rc6.gc56d2601b5d0
> # arch : x86_64
> # nrcpus online : 24
> # nrcpus avail : 24
> # cpudesc : AMD Ryzen 9 3900X 12-Core Processor
> # cpuid : AuthenticAMD,23,113,0
> # total memory : 32884432 kB
> # cmdline : /home/acme/bin/perf record ls 
> # event : name = cycles:u, , id = { 85540, 85541, 85542, 85543, 85544, 85545, 85546, 85547, 85548, 85549, 85550, 85551, 85552, 85553, 85554, 85555, 85556, 85557, 85558, 85559, 85560, 85561, 85562, 85563 }, size = 120, { sample_period, sample_freq } = 4000, sample_type = IP|TID|TIME|PERIOD, read_format = ID, disabled = 1, inherit = 1, exclude_kernel = 1, mmap = 1, comm = 1, freq = 1, enable_on_exec = 1, task = 1, sample_id_all = 1, exclude_guest = 1, mmap2 = 1, comm_exec = 1, ksymbol = 1, bpf_event = 1
> # CPU_TOPOLOGY info available, use -I to display
> # NUMA_TOPOLOGY info available, use -I to display
> # pmu mappings: amd_df = 8, software = 1, ibs_op = 11, power = 14, ibs_fetch = 10, uprobe = 7, cpu = 4, amd_iommu_0 = 12, breakpoint = 5, amd_l3 = 9, tracepoint = 2, kprobe = 6, msr = 13
> # CACHE info available, use -I to display
> # time of first sample : 12184.494971
> # time of last sample : 12184.495496
> # sample duration :      0.525 ms
> # MEM_TOPOLOGY info available, use -I to display
> # cpu pmu capabilities: max_precise=0
> # missing features: TRACING_DATA BRANCH_STACK GROUP_DESC AUXTRACE STAT CLOCKID DIR_FORMAT COMPRESSED CLOCK_DATA 
> # ========
> #
> 
> I.e. users would discover that using this control file is as easy as
> working with perf.data files or with the pipe mode, all the three ways
> of interacting with perf would use the same command interface arguments.

yep, I agree we can mimic the similar arguments, but I doubt we
can easily reuse the same code for that

jirka

Re: [PATCH 2/3] perf tools: Allow to enable/disable events via control file

[Arnaldo Carvalho de Melo]

Em Tue, Dec 15, 2020 at 04:24:20PM +0100, Jiri Olsa escreveu:
> On Tue, Dec 15, 2020 at 12:14:13PM -0300, Arnaldo Carvalho de Melo wrote:
> > Em Thu, Dec 10, 2020 at 09:43:29PM +0100, Jiri Olsa escreveu:
> > > Adding new control events to enable/disable specific event.
> > > The interface string for control file are:
> > > 
> > >   'enable-<EVENT NAME>'
> > >   'disable-<EVENT NAME>'
> > 
> > Wwy do we have "enable-" as the "tag" for this?
> 
> the whole 'enable-' is prefix for command that enables specific event
> following '-' starts the event name
> 
> > 
> > Also is it possible to use "enable sched:*" and have that match what is
> > in the evlist and enable (or disable, if using "disable sched:*") what
> > matches?
> 
> yep, that should be possible to add
> 
> > 
> > This second suggestion can be done on top of this, i.e. as an
> > enhancement, but mixing up the command (enable, disable) with its
> > arguments looks strange.
> 
> the '-' determines that there's event name following,
> pure 'enable' switches on everything

I see it, but why not use the more natural ' ' space to separate the
command from its arguments? Just like in a bash command line, say?

I.e. why not:

  enable

to enable everything, and:

  enable sched:sched_switch

To enable just the "sched:sched_switch" event?

- Arnaldo

Re: [PATCH 3/3] perf tools: Add evlist/evlist-verbose control commands

[Arnaldo Carvalho de Melo]

Em Tue, Dec 15, 2020 at 04:59:11PM +0100, Jiri Olsa escreveu:
> On Tue, Dec 15, 2020 at 12:23:43PM -0300, Arnaldo Carvalho de Melo wrote:
> > Em Thu, Dec 10, 2020 at 09:43:30PM +0100, Jiri Olsa escreveu:
> > > Adding new control events to display all evlist events.
> > > 
> > > The interface string for control file is 'evlist' and
> > > 'evlist-verbose'.
> > 
> > Can't we pass args to such commands?
> > 
> > Then its just one event, i.e. "evlist", and -v can be passed to it.
> 
> it's possible but it adds another processing to the single record thread
> where we want to be fast

> but I agree it could be helpful to get the other output that evsel__fprintf
> can print, and we already call evsel__fprintf, so it's just a matter of
> setting 'struct perf_attr_details' properly
 
> I need to check, but perhaps we could use ' ' instead of '-' and have:
> 
>   echo 'evlist -v' > control
>   echo 'evlist -g' > control
>   echo 'evlist -F' > control
 
> and have:
 
>   echo 'enable cycles' > control
 
> instead of:
 
>   echo 'enable-cycles' > control
 
> I'd like to avoid any elaborate parsing logic..
 
> how about that?

Use space to separate command from its arguments, keep the same
experience as:

[acme@quaco ~]$ perf evlist -h

 Usage: perf evlist [<options>]

    -f, --force           don't complain, do it
    -F, --freq            Show the sample frequency
    -g, --group           Show event group information
    -i, --input <file>    Input file name
    -v, --verbose         Show all event attr details
        --trace-fields    Show tracepoint fields

[acme@quaco ~]$

and:

echo "evlist arguments"

?

Fits the bill :-)

The experience users have on existing commands, the same arguments, etc.

Even -h can have its uses, i.e. has this daemon support for some option
or is it an old version?

- Arnaldo
 
> > 
> > i.e.:
> > 
> > The commands would be:
> > 
> > evlist
> > 
> > That produces:
> > 
> >  
> >    terminal 2:
> >      # echo evlist > control
> >  
> >    terminal 1:
> >      # perf record --control=fifo:control,ack -e 'sched:*'
> >      ...
> >      sched:sched_kthread_stop
> >      sched:sched_kthread_stop_ret
> >      sched:sched_waking
> > 
> > And 'evlist -v', that produces:
> > 
> >    terminal 2:
> >      # echo "evlist -v" > control
> >  
> >    terminal 1:
> >      ...
> >      sched:sched_kthread_stop: type: 2, size: 120, config: 0x145,      \
> >      { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU   \
> >      |PERIOD|RAW|IDENTIFIER, read_format: ID, disabled: 1, inherit:    \
> >      1, sample_id_all: 1, exclude_guest: 1
> >      sched:sched_kthread_stop_ret: type: 2, size: 120, config: 0x144   \
> >      , { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU \
> >      |PERIOD|RAW|IDENTIFIER, read_format: ID, disabled: 1, inherit: 1, \
> >      sample_id_all: 1, exclude_guest: 1
> >      ...
> > 
> > I think we could even change things such that we pass a file descriptor
> > for cmd_evlist to use, passing the argv received from the control file,
> > etc.
> 
> hum, so perf evlist opens/reads perf.data, which we do not have ready
> at that point in perf record
> 
> > 
> > With this in place we could reuse more stuff and allow using this
> > control file to obtain information such as 'perf report --header-only',
> > etc.
> > 
> > echo "report --header-only" > control would get us the same thing as
> > 'perf report --header-only' for an existing perf.data file:
> 
> all those header data are written when record is exiting or dumped
> for switch output, so we don't have that data at that moment control
> command is received
> 
> > 
> > 
> > # perf report --header-only
> > # ========
> > # captured on    : Tue Dec 15 12:21:23 2020
> > # header version : 1
> > # data offset    : 432
> > # data size      : 1648
> > # feat offset    : 2080
> > # hostname : five
> > # os release : 5.10.0-rc7+
> > # perf version : 5.10.rc6.gc56d2601b5d0
> > # arch : x86_64
> > # nrcpus online : 24
> > # nrcpus avail : 24
> > # cpudesc : AMD Ryzen 9 3900X 12-Core Processor
> > # cpuid : AuthenticAMD,23,113,0
> > # total memory : 32884432 kB
> > # cmdline : /home/acme/bin/perf record ls 
> > # event : name = cycles:u, , id = { 85540, 85541, 85542, 85543, 85544, 85545, 85546, 85547, 85548, 85549, 85550, 85551, 85552, 85553, 85554, 85555, 85556, 85557, 85558, 85559, 85560, 85561, 85562, 85563 }, size = 120, { sample_period, sample_freq } = 4000, sample_type = IP|TID|TIME|PERIOD, read_format = ID, disabled = 1, inherit = 1, exclude_kernel = 1, mmap = 1, comm = 1, freq = 1, enable_on_exec = 1, task = 1, sample_id_all = 1, exclude_guest = 1, mmap2 = 1, comm_exec = 1, ksymbol = 1, bpf_event = 1
> > # CPU_TOPOLOGY info available, use -I to display
> > # NUMA_TOPOLOGY info available, use -I to display
> > # pmu mappings: amd_df = 8, software = 1, ibs_op = 11, power = 14, ibs_fetch = 10, uprobe = 7, cpu = 4, amd_iommu_0 = 12, breakpoint = 5, amd_l3 = 9, tracepoint = 2, kprobe = 6, msr = 13
> > # CACHE info available, use -I to display
> > # time of first sample : 12184.494971
> > # time of last sample : 12184.495496
> > # sample duration :      0.525 ms
> > # MEM_TOPOLOGY info available, use -I to display
> > # cpu pmu capabilities: max_precise=0
> > # missing features: TRACING_DATA BRANCH_STACK GROUP_DESC AUXTRACE STAT CLOCKID DIR_FORMAT COMPRESSED CLOCK_DATA 
> > # ========
> > #
> > 
> > I.e. users would discover that using this control file is as easy as
> > working with perf.data files or with the pipe mode, all the three ways
> > of interacting with perf would use the same command interface arguments.
> 
> yep, I agree we can mimic the similar arguments, but I doubt we
> can easily reuse the same code for that
> 
> jirka
> 

-- 

- Arnaldo

Re: [PATCH 2/3] perf tools: Allow to enable/disable events via control file

[Jiri Olsa]

On Tue, Dec 15, 2020 at 01:03:32PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Tue, Dec 15, 2020 at 04:24:20PM +0100, Jiri Olsa escreveu:
> > On Tue, Dec 15, 2020 at 12:14:13PM -0300, Arnaldo Carvalho de Melo wrote:
> > > Em Thu, Dec 10, 2020 at 09:43:29PM +0100, Jiri Olsa escreveu:
> > > > Adding new control events to enable/disable specific event.
> > > > The interface string for control file are:
> > > > 
> > > >   'enable-<EVENT NAME>'
> > > >   'disable-<EVENT NAME>'
> > > 
> > > Wwy do we have "enable-" as the "tag" for this?
> > 
> > the whole 'enable-' is prefix for command that enables specific event
> > following '-' starts the event name
> > 
> > > 
> > > Also is it possible to use "enable sched:*" and have that match what is
> > > in the evlist and enable (or disable, if using "disable sched:*") what
> > > matches?
> > 
> > yep, that should be possible to add
> > 
> > > 
> > > This second suggestion can be done on top of this, i.e. as an
> > > enhancement, but mixing up the command (enable, disable) with its
> > > arguments looks strange.
> > 
> > the '-' determines that there's event name following,
> > pure 'enable' switches on everything
> 
> I see it, but why not use the more natural ' ' space to separate the
> command from its arguments? Just like in a bash command line, say?
> 
> I.e. why not:
> 
>   enable
> 
> to enable everything, and:
> 
>   enable sched:sched_switch
> 
> To enable just the "sched:sched_switch" event?

right, that's we discussed in the other patch thread,
I'll make the change

thanks,
jirka

Re: [PATCH 2/3] perf tools: Allow to enable/disable events via control file

[Arnaldo Carvalho de Melo]

Em Tue, Dec 15, 2020 at 05:18:38PM +0100, Jiri Olsa escreveu:
> On Tue, Dec 15, 2020 at 01:03:32PM -0300, Arnaldo Carvalho de Melo wrote:
> > I see it, but why not use the more natural ' ' space to separate the
> > command from its arguments? Just like in a bash command line, say?

> > I.e. why not:

> >   enable

> > to enable everything, and:

> >   enable sched:sched_switch

> > To enable just the "sched:sched_switch" event?
 
> right, that's we discussed in the other patch thread,
> I'll make the change

This is a new way to control perf, its important that we try to reuse
the same concepts as in the pre-existing forms of interaction, so as to
reduce the learning curve for using this control mode.

I.e. this 'enable' should be as equivalent to the -e argument as
possible, for what makes sense for a pre-existing, already configured
event.

For _adding_ new ones, that we probably will want next, then its even
more important to reuse the same -e parser :-)

Thanks!

- Arnaldo

Re: [PATCH 3/3] perf tools: Add evlist/evlist-verbose control commands

[Jiri Olsa]

On Tue, Dec 15, 2020 at 01:09:33PM -0300, Arnaldo Carvalho de Melo wrote:

SNIP

> > instead of:
>  
> >   echo 'enable-cycles' > control
>  
> > I'd like to avoid any elaborate parsing logic..
>  
> > how about that?
> 
> Use space to separate command from its arguments, keep the same
> experience as:
> 
> [acme@quaco ~]$ perf evlist -h
> 
>  Usage: perf evlist [<options>]
> 
>     -f, --force           don't complain, do it
>     -F, --freq            Show the sample frequency
>     -g, --group           Show event group information
>     -i, --input <file>    Input file name
>     -v, --verbose         Show all event attr details
>         --trace-fields    Show tracepoint fields
> 
> [acme@quaco ~]$
> 
> and:
> 
> echo "evlist arguments"
> 
> ?
> 
> Fits the bill :-)

ok

> 
> The experience users have on existing commands, the same arguments, etc.
> 
> Even -h can have its uses, i.e. has this daemon support for some option
> or is it an old version?

Alexei just suggested to add 'stop' control command and use it
instead of kill signal, which is good idea

but other than that daemon just opens the control file and
shows its path

jirka