* [PATCH v1] perf stat: enable 1ms interval for printing event counters values
@ 2018-04-03 15:04 Alexey Budankov
2018-04-03 15:22 ` Jiri Olsa
0 siblings, 1 reply; 3+ messages in thread
From: Alexey Budankov @ 2018-04-03 15:04 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo
Cc: Alexander Shishkin, Jiri Olsa, Namhyung Kim, Andi Kleen, linux-kernel
Currently print count interval for performance counters values is
limited by 10ms so reading the values at frequencies higher than 100Hz
is restricted by the tool.
This change makes perf stat -I possible on frequencies up to 1KHz and,
to some extent, makes perf stat -I to be on-par with perf record
sampling profiling.
When running perf stat -I for monitoring e.g. PCIe uncore counters and
at the same time profiling some I/O workload by perf record e.g. for
cpu-cycles and context switches, it is then possible to observe
consolidated CPU/OS/IO(Uncore) performance picture for that workload.
Tool overhead warning printed when specifying -v option can be missed
due to screen scrolling in case you have output to the console
so message is moved into help available by running perf stat -h.
Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
---
tools/perf/builtin-stat.c | 14 ++------------
1 file changed, 2 insertions(+), 12 deletions(-)
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index f5c454855908..147a27e8c937 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -1943,7 +1943,8 @@ static const struct option stat_options[] = {
OPT_STRING(0, "post", &post_cmd, "command",
"command to run after to the measured command"),
OPT_UINTEGER('I', "interval-print", &stat_config.interval,
- "print counts at regular interval in ms (>= 10)"),
+ "print counts at regular interval in ms "
+ "(overhead is possible for values <= 100ms)"),
OPT_INTEGER(0, "interval-count", &stat_config.times,
"print counts for fixed number of times"),
OPT_UINTEGER(0, "timeout", &stat_config.timeout,
@@ -2923,17 +2924,6 @@ int cmd_stat(int argc, const char **argv)
}
}
- if (interval && interval < 100) {
- if (interval < 10) {
- pr_err("print interval must be >= 10ms\n");
- parse_options_usage(stat_usage, stat_options, "I", 1);
- goto out;
- } else
- pr_warning("print interval < 100ms. "
- "The overhead percentage could be high in some cases. "
- "Please proceed with caution.\n");
- }
-
if (stat_config.times && interval)
interval_count = true;
else if (stat_config.times && !interval) {
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v1] perf stat: enable 1ms interval for printing event counters values
2018-04-03 15:04 [PATCH v1] perf stat: enable 1ms interval for printing event counters values Alexey Budankov
@ 2018-04-03 15:22 ` Jiri Olsa
2018-04-03 18:03 ` Alexey Budankov
0 siblings, 1 reply; 3+ messages in thread
From: Jiri Olsa @ 2018-04-03 15:22 UTC (permalink / raw)
To: Alexey Budankov
Cc: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Alexander Shishkin, Namhyung Kim, Andi Kleen, linux-kernel
On Tue, Apr 03, 2018 at 06:04:13PM +0300, Alexey Budankov wrote:
>
> Currently print count interval for performance counters values is
> limited by 10ms so reading the values at frequencies higher than 100Hz
> is restricted by the tool.
>
> This change makes perf stat -I possible on frequencies up to 1KHz and,
> to some extent, makes perf stat -I to be on-par with perf record
> sampling profiling.
>
> When running perf stat -I for monitoring e.g. PCIe uncore counters and
> at the same time profiling some I/O workload by perf record e.g. for
> cpu-cycles and context switches, it is then possible to observe
> consolidated CPU/OS/IO(Uncore) performance picture for that workload.
>
> Tool overhead warning printed when specifying -v option can be missed
> due to screen scrolling in case you have output to the console
> so message is moved into help available by running perf stat -h.
>
> Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
> ---
> tools/perf/builtin-stat.c | 14 ++------------
> 1 file changed, 2 insertions(+), 12 deletions(-)
I don't mind taking out the limit, but please update also
the stat man page, it mentiones the 10ms minimum
thanks,
jirka
>
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index f5c454855908..147a27e8c937 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -1943,7 +1943,8 @@ static const struct option stat_options[] = {
> OPT_STRING(0, "post", &post_cmd, "command",
> "command to run after to the measured command"),
> OPT_UINTEGER('I', "interval-print", &stat_config.interval,
> - "print counts at regular interval in ms (>= 10)"),
> + "print counts at regular interval in ms "
> + "(overhead is possible for values <= 100ms)"),
> OPT_INTEGER(0, "interval-count", &stat_config.times,
> "print counts for fixed number of times"),
> OPT_UINTEGER(0, "timeout", &stat_config.timeout,
> @@ -2923,17 +2924,6 @@ int cmd_stat(int argc, const char **argv)
> }
> }
>
> - if (interval && interval < 100) {
> - if (interval < 10) {
> - pr_err("print interval must be >= 10ms\n");
> - parse_options_usage(stat_usage, stat_options, "I", 1);
> - goto out;
> - } else
> - pr_warning("print interval < 100ms. "
> - "The overhead percentage could be high in some cases. "
> - "Please proceed with caution.\n");
> - }
> -
> if (stat_config.times && interval)
> interval_count = true;
> else if (stat_config.times && !interval) {
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v1] perf stat: enable 1ms interval for printing event counters values
2018-04-03 15:22 ` Jiri Olsa
@ 2018-04-03 18:03 ` Alexey Budankov
0 siblings, 0 replies; 3+ messages in thread
From: Alexey Budankov @ 2018-04-03 18:03 UTC (permalink / raw)
To: Jiri Olsa
Cc: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Alexander Shishkin, Namhyung Kim, Andi Kleen, linux-kernel
On 03.04.2018 18:22, Jiri Olsa wrote:
> On Tue, Apr 03, 2018 at 06:04:13PM +0300, Alexey Budankov wrote:
>>
>> Currently print count interval for performance counters values is
>> limited by 10ms so reading the values at frequencies higher than 100Hz
>> is restricted by the tool.
>>
>> This change makes perf stat -I possible on frequencies up to 1KHz and,
>> to some extent, makes perf stat -I to be on-par with perf record
>> sampling profiling.
>>
>> When running perf stat -I for monitoring e.g. PCIe uncore counters and
>> at the same time profiling some I/O workload by perf record e.g. for
>> cpu-cycles and context switches, it is then possible to observe
>> consolidated CPU/OS/IO(Uncore) performance picture for that workload.
>>
>> Tool overhead warning printed when specifying -v option can be missed
>> due to screen scrolling in case you have output to the console
>> so message is moved into help available by running perf stat -h.
>>
>> Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
>> ---
>> tools/perf/builtin-stat.c | 14 ++------------
>> 1 file changed, 2 insertions(+), 12 deletions(-)
>
> I don't mind taking out the limit, but please update also
> the stat man page, it mentiones the 10ms minimum
Yep, will do. Thanks for noticing this.
Thanks,
Alexey
>
> thanks,
> jirka
>
>>
>> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
>> index f5c454855908..147a27e8c937 100644
>> --- a/tools/perf/builtin-stat.c
>> +++ b/tools/perf/builtin-stat.c
>> @@ -1943,7 +1943,8 @@ static const struct option stat_options[] = {
>> OPT_STRING(0, "post", &post_cmd, "command",
>> "command to run after to the measured command"),
>> OPT_UINTEGER('I', "interval-print", &stat_config.interval,
>> - "print counts at regular interval in ms (>= 10)"),
>> + "print counts at regular interval in ms "
>> + "(overhead is possible for values <= 100ms)"),
>> OPT_INTEGER(0, "interval-count", &stat_config.times,
>> "print counts for fixed number of times"),
>> OPT_UINTEGER(0, "timeout", &stat_config.timeout,
>> @@ -2923,17 +2924,6 @@ int cmd_stat(int argc, const char **argv)
>> }
>> }
>>
>> - if (interval && interval < 100) {
>> - if (interval < 10) {
>> - pr_err("print interval must be >= 10ms\n");
>> - parse_options_usage(stat_usage, stat_options, "I", 1);
>> - goto out;
>> - } else
>> - pr_warning("print interval < 100ms. "
>> - "The overhead percentage could be high in some cases. "
>> - "Please proceed with caution.\n");
>> - }
>> -
>> if (stat_config.times && interval)
>> interval_count = true;
>> else if (stat_config.times && !interval) {
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2018-04-03 15:04 [PATCH v1] perf stat: enable 1ms interval for printing event counters values Alexey Budankov
2018-04-03 15:22 ` Jiri Olsa
2018-04-03 18:03 ` Alexey Budankov
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