* [PATCH v2 0/2] Reset CPU mask
@ 2019-10-01 14:57 Tzvetomir Stoyanov (VMware)
2019-10-01 14:57 ` [PATCH v2 1/2] trace-cmd: Reset CPU mask after setting it in trace-cmd record with option -M Tzvetomir Stoyanov (VMware)
` (2 more replies)
0 siblings, 3 replies; 7+ messages in thread
From: Tzvetomir Stoyanov (VMware) @ 2019-10-01 14:57 UTC (permalink / raw)
To: rostedt; +Cc: linux-trace-devel
Reset CPU mask:
- After setting it in trace-cmd record with option -M, to its previous
value.
- By the "trace-cmd reset" command, to its default value - all CPUs are
enabled for tracing.
Fixes https://bugzilla.kernel.org/show_bug.cgi?id=204941
[
v2 changes:
Addressed Steven Rostedt and Eugene Syromyatnikov <evgsyr@gmail.com>
comments about the correct cpu mask in case we have more than 32 CPUs.
]
Tzvetomir Stoyanov (VMware) (2):
trace-cmd: Reset CPU mask after setting it in trace-cmd record with
option -M
trace-cmd: Reset CPU mask to its default value with "trace-cmd reset".
tracecmd/trace-record.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
--
2.21.0
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v2 1/2] trace-cmd: Reset CPU mask after setting it in trace-cmd record with option -M
2019-10-01 14:57 [PATCH v2 0/2] Reset CPU mask Tzvetomir Stoyanov (VMware)
@ 2019-10-01 14:57 ` Tzvetomir Stoyanov (VMware)
2019-10-01 14:57 ` [PATCH v2 2/2] trace-cmd: Reset CPU mask to its default value with "trace-cmd reset" Tzvetomir Stoyanov (VMware)
2019-10-03 14:44 ` [PATCH v2 3/2] trace-cmd: Optimize the logic of reset_cpu_mask() Steven Rostedt
2 siblings, 0 replies; 7+ messages in thread
From: Tzvetomir Stoyanov (VMware) @ 2019-10-01 14:57 UTC (permalink / raw)
To: rostedt; +Cc: linux-trace-devel
When trace-cmd is run with option -M, to set the tracing cpumask, it was not reset
to its previous state. The trace-cmd record should put back the original value
after using -M for the tracing cpu masks.
Fixes https://bugzilla.kernel.org/show_bug.cgi?id=204941
Reported-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
tracecmd/trace-record.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 96d2c1a..69de82a 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -2403,6 +2403,7 @@ static void set_mask(struct buffer_instance *instance)
path = get_instance_file(instance, "tracing_cpumask");
if (!path)
die("could not allocate path");
+ reset_save_file(path, RESET_DEFAULT_PRIO);
ret = stat(path, &st);
if (ret < 0) {
--
2.21.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH v2 2/2] trace-cmd: Reset CPU mask to its default value with "trace-cmd reset".
2019-10-01 14:57 [PATCH v2 0/2] Reset CPU mask Tzvetomir Stoyanov (VMware)
2019-10-01 14:57 ` [PATCH v2 1/2] trace-cmd: Reset CPU mask after setting it in trace-cmd record with option -M Tzvetomir Stoyanov (VMware)
@ 2019-10-01 14:57 ` Tzvetomir Stoyanov (VMware)
2019-10-01 15:32 ` Steven Rostedt
2019-10-03 14:44 ` [PATCH v2 3/2] trace-cmd: Optimize the logic of reset_cpu_mask() Steven Rostedt
2 siblings, 1 reply; 7+ messages in thread
From: Tzvetomir Stoyanov (VMware) @ 2019-10-01 14:57 UTC (permalink / raw)
To: rostedt; +Cc: linux-trace-devel
"trace-cmd reset" command should put all ftrace config to its default
state, but trace cpumask was not reseted. The patch sets cpumask to
its default value - all CPUs are enabled for tracing.
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
tracecmd/trace-record.c | 35 +++++++++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 69de82a..6f3520c 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -4096,6 +4096,40 @@ static void reset_clock(void)
write_instance_file(instance, "trace_clock", "local", "clock");
}
+static void reset_cpu_mask(void)
+{
+ struct buffer_instance *instance;
+ int cpus = count_cpus();
+ int fullwords;
+ char *buf;
+ int bits;
+ int len;
+
+ fullwords = cpus / 32;
+ bits = cpus % 32;
+ len = (fullwords + 1) * 9;
+
+ buf = malloc(len + 1);
+ if (!buf) {
+ warning("Unable to allocate %d bytes for cpu mask", len + 1);
+ return;
+ }
+ buf[0] = '\0';
+ if (bits) {
+ sprintf(buf, "%x", (1 << bits) - 1);
+ } else if (fullwords) {
+ strcat(buf, "ffffffff");
+ fullwords--;
+ }
+ while (fullwords-- > 0)
+ strcat(buf, ",ffffffff");
+
+ for_all_instances(instance)
+ write_instance_file(instance, "tracing_cpumask", buf, "cpumask");
+
+ free(buf);
+}
+
static void reset_event_pid(void)
{
add_event_pid("");
@@ -4808,6 +4842,7 @@ void trace_reset(int argc, char **argv)
reset_clock();
reset_event_pid();
reset_max_latency_instance();
+ reset_cpu_mask();
tracecmd_remove_instances();
clear_func_filters();
/* restore tracing_on to 1 */
--
2.21.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH v2 2/2] trace-cmd: Reset CPU mask to its default value with "trace-cmd reset".
2019-10-01 14:57 ` [PATCH v2 2/2] trace-cmd: Reset CPU mask to its default value with "trace-cmd reset" Tzvetomir Stoyanov (VMware)
@ 2019-10-01 15:32 ` Steven Rostedt
2019-10-01 15:37 ` Tzvetomir Stoyanov
0 siblings, 1 reply; 7+ messages in thread
From: Steven Rostedt @ 2019-10-01 15:32 UTC (permalink / raw)
To: Tzvetomir Stoyanov (VMware); +Cc: linux-trace-devel
On Tue, 1 Oct 2019 17:57:40 +0300
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:
> "trace-cmd reset" command should put all ftrace config to its default
> state, but trace cpumask was not reseted. The patch sets cpumask to
> its default value - all CPUs are enabled for tracing.
>
> Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
> ---
> tracecmd/trace-record.c | 35 +++++++++++++++++++++++++++++++++++
> 1 file changed, 35 insertions(+)
>
> diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
> index 69de82a..6f3520c 100644
> --- a/tracecmd/trace-record.c
> +++ b/tracecmd/trace-record.c
> @@ -4096,6 +4096,40 @@ static void reset_clock(void)
> write_instance_file(instance, "trace_clock", "local", "clock");
> }
>
> +static void reset_cpu_mask(void)
> +{
> + struct buffer_instance *instance;
> + int cpus = count_cpus();
> + int fullwords;
> + char *buf;
> + int bits;
> + int len;
> +
> + fullwords = cpus / 32;
> + bits = cpus % 32;
> + len = (fullwords + 1) * 9;
> +
> + buf = malloc(len + 1);
> + if (!buf) {
> + warning("Unable to allocate %d bytes for cpu mask", len + 1);
> + return;
> + }
> + buf[0] = '\0';
> + if (bits) {
> + sprintf(buf, "%x", (1 << bits) - 1);
> + } else if (fullwords) {
> + strcat(buf, "ffffffff");
> + fullwords--;
> + }
> + while (fullwords-- > 0)
> + strcat(buf, ",ffffffff");
I like my way because it's a little more condensed ;-)
But this works too and it's far from a fast path. As it's probably
more readable, I'll all this one.
-- Steve
> +
> + for_all_instances(instance)
> + write_instance_file(instance, "tracing_cpumask", buf, "cpumask");
> +
> + free(buf);
> +}
> +
> static void reset_event_pid(void)
> {
> add_event_pid("");
> @@ -4808,6 +4842,7 @@ void trace_reset(int argc, char **argv)
> reset_clock();
> reset_event_pid();
> reset_max_latency_instance();
> + reset_cpu_mask();
> tracecmd_remove_instances();
> clear_func_filters();
> /* restore tracing_on to 1 */
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2 2/2] trace-cmd: Reset CPU mask to its default value with "trace-cmd reset".
2019-10-01 15:32 ` Steven Rostedt
@ 2019-10-01 15:37 ` Tzvetomir Stoyanov
2019-10-01 15:45 ` Steven Rostedt
0 siblings, 1 reply; 7+ messages in thread
From: Tzvetomir Stoyanov @ 2019-10-01 15:37 UTC (permalink / raw)
To: Steven Rostedt; +Cc: linux-trace-devel
On Tue, Oct 1, 2019 at 6:32 PM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Tue, 1 Oct 2019 17:57:40 +0300
> "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:
>
> > "trace-cmd reset" command should put all ftrace config to its default
> > state, but trace cpumask was not reseted. The patch sets cpumask to
> > its default value - all CPUs are enabled for tracing.
> >
> > Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
> > ---
> > tracecmd/trace-record.c | 35 +++++++++++++++++++++++++++++++++++
> > 1 file changed, 35 insertions(+)
> >
> > diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
> > index 69de82a..6f3520c 100644
> > --- a/tracecmd/trace-record.c
> > +++ b/tracecmd/trace-record.c
> > @@ -4096,6 +4096,40 @@ static void reset_clock(void)
> > write_instance_file(instance, "trace_clock", "local", "clock");
> > }
> >
> > +static void reset_cpu_mask(void)
> > +{
> > + struct buffer_instance *instance;
> > + int cpus = count_cpus();
> > + int fullwords;
> > + char *buf;
> > + int bits;
> > + int len;
> > +
> > + fullwords = cpus / 32;
> > + bits = cpus % 32;
> > + len = (fullwords + 1) * 9;
> > +
> > + buf = malloc(len + 1);
> > + if (!buf) {
> > + warning("Unable to allocate %d bytes for cpu mask", len + 1);
> > + return;
> > + }
> > + buf[0] = '\0';
> > + if (bits) {
> > + sprintf(buf, "%x", (1 << bits) - 1);
> > + } else if (fullwords) {
> > + strcat(buf, "ffffffff");
> > + fullwords--;
> > + }
> > + while (fullwords-- > 0)
> > + strcat(buf, ",ffffffff");
>
> I like my way because it's a little more condensed ;-)
>
> But this works too and it's far from a fast path. As it's probably
> more readable, I'll all this one.
>
> -- Steve
>
Actually the only change here is to handle the case when bits is 0,
not to put the leading ",".
The ftrace complains with "Invalid argument" in that case.
>
> > +
> > + for_all_instances(instance)
> > + write_instance_file(instance, "tracing_cpumask", buf, "cpumask");
> > +
> > + free(buf);
> > +}
> > +
> > static void reset_event_pid(void)
> > {
> > add_event_pid("");
> > @@ -4808,6 +4842,7 @@ void trace_reset(int argc, char **argv)
> > reset_clock();
> > reset_event_pid();
> > reset_max_latency_instance();
> > + reset_cpu_mask();
> > tracecmd_remove_instances();
> > clear_func_filters();
> > /* restore tracing_on to 1 */
>
--
Tzvetomir (Ceco) Stoyanov
VMware Open Source Technology Center
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2 2/2] trace-cmd: Reset CPU mask to its default value with "trace-cmd reset".
2019-10-01 15:37 ` Tzvetomir Stoyanov
@ 2019-10-01 15:45 ` Steven Rostedt
0 siblings, 0 replies; 7+ messages in thread
From: Steven Rostedt @ 2019-10-01 15:45 UTC (permalink / raw)
To: Tzvetomir Stoyanov; +Cc: linux-trace-devel
On Tue, 1 Oct 2019 18:37:54 +0300
Tzvetomir Stoyanov <tz.stoyanov@gmail.com> wrote:
> On Tue, Oct 1, 2019 at 6:32 PM Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> > On Tue, 1 Oct 2019 17:57:40 +0300
> > "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:
> >
> > > "trace-cmd reset" command should put all ftrace config to its default
> > > state, but trace cpumask was not reseted. The patch sets cpumask to
> > > its default value - all CPUs are enabled for tracing.
> > >
> > > Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
> > > ---
> > > tracecmd/trace-record.c | 35 +++++++++++++++++++++++++++++++++++
> > > 1 file changed, 35 insertions(+)
> > >
> > > diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
> > > index 69de82a..6f3520c 100644
> > > --- a/tracecmd/trace-record.c
> > > +++ b/tracecmd/trace-record.c
> > > @@ -4096,6 +4096,40 @@ static void reset_clock(void)
> > > write_instance_file(instance, "trace_clock", "local", "clock");
> > > }
> > >
> > > +static void reset_cpu_mask(void)
> > > +{
> > > + struct buffer_instance *instance;
> > > + int cpus = count_cpus();
> > > + int fullwords;
> > > + char *buf;
> > > + int bits;
> > > + int len;
> > > +
> > > + fullwords = cpus / 32;
> > > + bits = cpus % 32;
> > > + len = (fullwords + 1) * 9;
> > > +
> > > + buf = malloc(len + 1);
> > > + if (!buf) {
> > > + warning("Unable to allocate %d bytes for cpu mask", len + 1);
> > > + return;
> > > + }
> > > + buf[0] = '\0';
> > > + if (bits) {
> > > + sprintf(buf, "%x", (1 << bits) - 1);
> > > + } else if (fullwords) {
> > > + strcat(buf, "ffffffff");
> > > + fullwords--;
> > > + }
> > > + while (fullwords-- > 0)
> > > + strcat(buf, ",ffffffff");
> >
> > I like my way because it's a little more condensed ;-)
> >
> > But this works too and it's far from a fast path. As it's probably
> > more readable, I'll all this one.
> >
> > -- Steve
> >
> Actually the only change here is to handle the case when bits is 0,
> not to put the leading ",".
> The ftrace complains with "Invalid argument" in that case.
>
Mine handled that case too. The difference was the "cpus - 1" part of
my code:
fullwords = (cpus - 1) / 32; <--
bits = (cpus - 1) % 32 + 1; <--
len = (fullwords + 1) * 9;
buf = malloc(len + 1);
buf[0] = '\0';
if (bits)
sprintf(buf, "%x", (unsigned int)((1ULL << bits) - 1));
while (fullwords-- > 0)
strcat(buf, ",ffffffff");
The output of yours and mine were identical. When cpus was a power of
32, it would still have one less of "fullwords", and bits would be 32.
Which is why I needed to add "1ULL" to make:
(1 << 32) - 1 == 0xffffffff
the fullwords was only for non bits.
-- Steve
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v2 3/2] trace-cmd: Optimize the logic of reset_cpu_mask()
2019-10-01 14:57 [PATCH v2 0/2] Reset CPU mask Tzvetomir Stoyanov (VMware)
2019-10-01 14:57 ` [PATCH v2 1/2] trace-cmd: Reset CPU mask after setting it in trace-cmd record with option -M Tzvetomir Stoyanov (VMware)
2019-10-01 14:57 ` [PATCH v2 2/2] trace-cmd: Reset CPU mask to its default value with "trace-cmd reset" Tzvetomir Stoyanov (VMware)
@ 2019-10-03 14:44 ` Steven Rostedt
2 siblings, 0 replies; 7+ messages in thread
From: Steven Rostedt @ 2019-10-03 14:44 UTC (permalink / raw)
To: Tzvetomir Stoyanov (VMware); +Cc: linux-trace-devel
From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Change the logic of reset_cpu_mask() to be a little more condensed, and also
move the buffer onto the stack and eliminate the warning message as we no
longer need to use malloc.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
tracecmd/trace-record.c | 25 ++++++-------------------
1 file changed, 6 insertions(+), 19 deletions(-)
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 6f3520cc..cfe67f90 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -4100,27 +4100,14 @@ static void reset_cpu_mask(void)
{
struct buffer_instance *instance;
int cpus = count_cpus();
- int fullwords;
- char *buf;
- int bits;
- int len;
+ int fullwords = (cpus - 1) / 32;
+ int bits = (cpus - 1) % 32 + 1;
+ int len = (fullwords + 1) * 9;
+ char buf[len + 1];
- fullwords = cpus / 32;
- bits = cpus % 32;
- len = (fullwords + 1) * 9;
-
- buf = malloc(len + 1);
- if (!buf) {
- warning("Unable to allocate %d bytes for cpu mask", len + 1);
- return;
- }
buf[0] = '\0';
- if (bits) {
- sprintf(buf, "%x", (1 << bits) - 1);
- } else if (fullwords) {
- strcat(buf, "ffffffff");
- fullwords--;
- }
+
+ sprintf(buf, "%x", (unsigned int)((1ULL << bits) - 1));
while (fullwords-- > 0)
strcat(buf, ",ffffffff");
--
2.20.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
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2019-10-01 14:57 [PATCH v2 0/2] Reset CPU mask Tzvetomir Stoyanov (VMware)
2019-10-01 14:57 ` [PATCH v2 1/2] trace-cmd: Reset CPU mask after setting it in trace-cmd record with option -M Tzvetomir Stoyanov (VMware)
2019-10-01 14:57 ` [PATCH v2 2/2] trace-cmd: Reset CPU mask to its default value with "trace-cmd reset" Tzvetomir Stoyanov (VMware)
2019-10-01 15:32 ` Steven Rostedt
2019-10-01 15:37 ` Tzvetomir Stoyanov
2019-10-01 15:45 ` Steven Rostedt
2019-10-03 14:44 ` [PATCH v2 3/2] trace-cmd: Optimize the logic of reset_cpu_mask() Steven Rostedt
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