From: Steven Rostedt <rostedt@goodmis.org>
To: linux-trace-devel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, Tom Zanussi <zanussi@kernel.org>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
linux-rt-users <linux-rt-users@vger.kernel.org>,
Clark Williams <williams@redhat.com>,
"Steven Rostedt (VMware)" <rostedt@goodmis.org>
Subject: [PATCH 4/7] libtracefs: Add API tracefs_synth_snapshot()
Date: Thu, 12 Aug 2021 22:16:52 -0400 [thread overview]
Message-ID: <20210813021655.939819-5-rostedt@goodmis.org> (raw)
In-Reply-To: <20210813021655.939819-1-rostedt@goodmis.org>
From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Add new API tracefs_synth_snapshot()
Where this will add "actions" to the synthetic event descriptor and also
add other features besides "onmatch()" such that the output can be:
onmax($lat).trace(latency,$lat):onmax($lat).snapshot
That will trace the latency when it hits a maximum, and also take a
snapshot of the buffer.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
Documentation/libtracefs-synth2.txt | 11 +++++++++-
include/tracefs.h | 2 ++
src/tracefs-hist.c | 34 +++++++++++++++++++++++++++++
3 files changed, 46 insertions(+), 1 deletion(-)
diff --git a/Documentation/libtracefs-synth2.txt b/Documentation/libtracefs-synth2.txt
index a74e88ec0eda..194a4e021f62 100644
--- a/Documentation/libtracefs-synth2.txt
+++ b/Documentation/libtracefs-synth2.txt
@@ -4,7 +4,7 @@ libtracefs(3)
NAME
----
tracefs_synth_create, tracefs_synth_destroy, tracefs_synth_show,tracefs_synth_complete,
-tracefs_synth_get_start_hist,tracefs_synth_trace - Creation of synthetic events
+tracefs_synth_get_start_hist,tracefs_synth_trace,tracefs_synth_snapshot - Creation of synthetic events
SYNOPSIS
--------
@@ -23,6 +23,8 @@ struct tracefs_hist pass:[*]tracefs_synth_get_start_hist(struct tracefs_synth pa
int tracefs_synth_trace(struct tracefs_synth pass:[*]synth,
enum tracefs_synth_handler type, const char pass:[*]var);
+int tracefs_synth_snapshot(struct tracefs_synth pass:[*]synth,
+ enum tracefs_synth_handler type, const char pass:[*]var);
--
DESCRIPTION
@@ -75,6 +77,13 @@ when the given variable _var_ hits a new max for the matching keys. Or
*TRACEFS_SYNTH_HANDLE_CHANGE* for when the _var_ changes. _var_ must be one of
the _name_ elements used in *tracefs_synth_add_end_field*(3).
+*tracefs_synth_snapshot*() When the given variable _var_ is either a new max if
+_handler_ is TRACEFS_SYNTH_HANDLE_MAX_ or simpy changed if TRACEFS_SYNTH_HANDLE_CHANGE_
+then take a "snapshot" of the buffer. The snapshot moves the normal "trace" buffer
+into a "snapshot" buffer, that can be accessed via the "snapshot" file in the
+top level tracefs directory, or one of the instances. _var_ changes. _var_ must be one of
+the _name_ elements used in *tracefs_synth_add_end_field*(3).
+
RETURN VALUE
------------
Returns zero on success or -1 on error.
diff --git a/include/tracefs.h b/include/tracefs.h
index 2faa564a860f..45a5bb2df2de 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -478,6 +478,8 @@ int tracefs_synth_append_end_filter(struct tracefs_synth *synth,
const char *val);
int tracefs_synth_trace(struct tracefs_synth *synth,
enum tracefs_synth_handler type, const char *field);
+int tracefs_synth_snapshot(struct tracefs_synth *synth,
+ enum tracefs_synth_handler type, const char *field);
bool tracefs_synth_complete(struct tracefs_synth *synth);
struct tracefs_hist *tracefs_synth_get_start_hist(struct tracefs_synth *synth);
int tracefs_synth_create(struct tracefs_instance *instance,
diff --git a/src/tracefs-hist.c b/src/tracefs-hist.c
index 562ec65088a9..2c9c37b8ec23 100644
--- a/src/tracefs-hist.c
+++ b/src/tracefs-hist.c
@@ -524,6 +524,7 @@ int tracefs_hist_append_filter(struct tracefs_hist *hist,
enum action_type {
ACTION_NONE,
ACTION_TRACE,
+ ACTION_SNAPSHOT,
};
struct action {
@@ -1414,6 +1415,36 @@ int tracefs_synth_trace(struct tracefs_synth *synth,
return 0;
}
+/**
+ * tracefs_synth_snapshot - create a snapshot command to the histogram
+ * @synth: The tracefs_synth descriptor
+ * @type: The type of handler to attach the snapshot action with
+ * @field: The field for handlers onmax and onchange
+ *
+ * Add the action to do a snapshot for handlers onmax and onchange.
+ *
+ * Returns 0 on succes, -1 on error.
+ */
+int tracefs_synth_snapshot(struct tracefs_synth *synth,
+ enum tracefs_synth_handler type, const char *field)
+{
+ struct action *action;
+
+ if (!synth || !field || (type == TRACEFS_SYNTH_HANDLE_MATCH)) {
+ errno = EINVAL;
+ return -1;
+ }
+
+ action = create_action(type, synth, field);
+ if (!action)
+ return -1;
+
+ action->type = ACTION_SNAPSHOT;
+ action->handler = type;
+ add_action(synth, action);
+ return 0;
+}
+
static char *create_synthetic_event(struct tracefs_synth *synth)
{
char *synthetic_event;
@@ -1562,6 +1593,9 @@ static char *create_actions(char *hist, struct tracefs_synth *synth)
case ACTION_TRACE:
hist = create_trace(hist, synth);
break;
+ case ACTION_SNAPSHOT:
+ hist = append_string(hist, NULL, ".snapshot()");
+ break;
default:
continue;
}
--
2.30.2
next prev parent reply other threads:[~2021-08-13 2:17 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-13 2:16 [PATCH 0/7] libtracefs: Add handlers 'onmax' and 'onchange' and actions 'snapshot' and 'save' Steven Rostedt
2021-08-13 2:16 ` [PATCH 1/7] libtracefs: Move creating of onmatch handler and trace action into helper functions Steven Rostedt
2021-08-13 2:16 ` [PATCH 2/7] libtracefs: Add logic to apply actions to synthetic events Steven Rostedt
2021-08-13 2:16 ` [PATCH 3/7] libtracefs: Add API tracefs_synth_trace() Steven Rostedt
2021-08-13 2:16 ` Steven Rostedt [this message]
2021-08-13 2:16 ` [PATCH 5/7] libtracefs: Add API tracefs_synth_save() Steven Rostedt
2021-08-13 2:16 ` [PATCH 6/7] libtracefs: Update the libtracefs-sql man page for the new tracefs_synth APIs Steven Rostedt
2021-08-13 2:16 ` [PATCH 7/7] libtracefs: Make a man page for the sqlhist man page example Steven Rostedt
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210813021655.939819-5-rostedt@goodmis.org \
--to=rostedt@goodmis.org \
--cc=bristot@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rt-users@vger.kernel.org \
--cc=linux-trace-devel@vger.kernel.org \
--cc=mhiramat@kernel.org \
--cc=namhyung@kernel.org \
--cc=williams@redhat.com \
--cc=zanussi@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).