[PATCH] perf stat: Skip duration_time in setup_system_wide

[PATCH] perf stat: Skip duration_time in setup_system_wide

[Jin Yao]

Some metrics (such as DRAM_BW_Use) consists of uncore events and
duration_time. For uncore events, counter->core.system_wide is
true. But for duration_time, counter->core.system_wide is false
so target.system_wide is set to false.

Then 'enable_on_exec' is set in perf_event_attr of uncore event.
Kernel will return error when trying to open the uncore event.

This patch skips the duration_time in setup_system_wide then
target.system_wide will be set to true for the evlist of uncore
events + duration_time.

Before (tested on skylake desktop):

 # perf stat -M DRAM_BW_Use -- sleep 1
 Error:
 The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (arb/event=0x84,umask=0x1/).
 /bin/dmesg | grep -i perf may provide additional information.

After:

 # perf stat -M DRAM_BW_Use -- sleep 1

  Performance counter stats for 'system wide':

                169      arb/event=0x84,umask=0x1/ #     0.00 DRAM_BW_Use
             40,427      arb/event=0x81,umask=0x1/
      1,000,902,197 ns   duration_time

        1.000902197 seconds time elapsed

Fixes: 648b5af3f3ae ("libperf: Move 'system_wide' from 'struct evsel' to 'struct perf_evsel'")
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
---
 tools/perf/builtin-stat.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 7f8d756d9408..9bcc93bc0973 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -2047,8 +2047,10 @@ static void setup_system_wide(int forks)
 		struct evsel *counter;
 
 		evlist__for_each_entry(evsel_list, counter) {
-			if (!counter->core.system_wide)
+			if (!counter->core.system_wide &&
+			    strcmp(counter->name, "duration_time")) {
 				return;
+			}
 		}
 
 		if (evsel_list->core.nr_entries)
-- 
2.17.1

Re: [PATCH] perf stat: Skip duration_time in setup_system_wide

[Arnaldo Carvalho de Melo]

Em Tue, Sep 22, 2020 at 09:50:04AM +0800, Jin Yao escreveu:
> Some metrics (such as DRAM_BW_Use) consists of uncore events and
> duration_time. For uncore events, counter->core.system_wide is
> true. But for duration_time, counter->core.system_wide is false
> so target.system_wide is set to false.
> 
> Then 'enable_on_exec' is set in perf_event_attr of uncore event.
> Kernel will return error when trying to open the uncore event.
> 
> This patch skips the duration_time in setup_system_wide then
> target.system_wide will be set to true for the evlist of uncore
> events + duration_time.
> 
> Before (tested on skylake desktop):
> 
>  # perf stat -M DRAM_BW_Use -- sleep 1
>  Error:
>  The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (arb/event=0x84,umask=0x1/).
>  /bin/dmesg | grep -i perf may provide additional information.
> 
> After:
> 
>  # perf stat -M DRAM_BW_Use -- sleep 1
> 
>   Performance counter stats for 'system wide':
> 
>                 169      arb/event=0x84,umask=0x1/ #     0.00 DRAM_BW_Use
>              40,427      arb/event=0x81,umask=0x1/
>       1,000,902,197 ns   duration_time
> 
>         1.000902197 seconds time elapsed
> 
> Fixes: 648b5af3f3ae ("libperf: Move 'system_wide' from 'struct evsel' to 'struct perf_evsel'")

Humm, what makes you think that this cset was the one introducing this
problem? It just moves evsel->system_wide to evsel->core.system_wide.

- Arnaldo


> Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
> ---
>  tools/perf/builtin-stat.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index 7f8d756d9408..9bcc93bc0973 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -2047,8 +2047,10 @@ static void setup_system_wide(int forks)
>  		struct evsel *counter;
>  
>  		evlist__for_each_entry(evsel_list, counter) {
> -			if (!counter->core.system_wide)
> +			if (!counter->core.system_wide &&
> +			    strcmp(counter->name, "duration_time")) {
>  				return;
> +			}
>  		}
>  
>  		if (evsel_list->core.nr_entries)
> -- 
> 2.17.1
> 

-- 

- Arnaldo

Re: [PATCH] perf stat: Skip duration_time in setup_system_wide

[Arnaldo Carvalho de Melo]

Em Tue, Sep 22, 2020 at 02:56:30PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Tue, Sep 22, 2020 at 09:50:04AM +0800, Jin Yao escreveu:
> > Some metrics (such as DRAM_BW_Use) consists of uncore events and
> > duration_time. For uncore events, counter->core.system_wide is
> > true. But for duration_time, counter->core.system_wide is false
> > so target.system_wide is set to false.
> > 
> > Then 'enable_on_exec' is set in perf_event_attr of uncore event.
> > Kernel will return error when trying to open the uncore event.
> > 
> > This patch skips the duration_time in setup_system_wide then
> > target.system_wide will be set to true for the evlist of uncore
> > events + duration_time.
> > 
> > Before (tested on skylake desktop):
> > 
> >  # perf stat -M DRAM_BW_Use -- sleep 1
> >  Error:
> >  The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (arb/event=0x84,umask=0x1/).
> >  /bin/dmesg | grep -i perf may provide additional information.
> > 
> > After:
> > 
> >  # perf stat -M DRAM_BW_Use -- sleep 1
> > 
> >   Performance counter stats for 'system wide':
> > 
> >                 169      arb/event=0x84,umask=0x1/ #     0.00 DRAM_BW_Use
> >              40,427      arb/event=0x81,umask=0x1/
> >       1,000,902,197 ns   duration_time
> > 
> >         1.000902197 seconds time elapsed
> > 
> > Fixes: 648b5af3f3ae ("libperf: Move 'system_wide' from 'struct evsel' to 'struct perf_evsel'")
> 
> Humm, what makes you think that this cset was the one introducing this
> problem? It just moves evsel->system_wide to evsel->core.system_wide.

Apart from that I reproduced the problem and after applying your patch
it seems cured:

  [acme@quaco perf]$ grep 'model name' -m1 /proc/cpuinfo
  model name	: Intel(R) Core(TM) i7-8650U CPU @ 1.90GHz

Before (with -v to see details):

  [root@quaco ~]# perf stat -v -M DRAM_BW_Use -- sleep 1
  Using CPUID GenuineIntel-6-8E-A
  metric expr 64 * ( arb@event\=0x81\,umask\=0x1@ + arb@event\=0x84\,umask\=0x1@ ) / 1000000 / duration_time / 1000 for DRAM_BW_Use
  found event duration_time
  found event arb/event=0x84,umask=0x1/
  found event arb/event=0x81,umask=0x1/
  adding {arb/event=0x84,umask=0x1/,arb/event=0x81,umask=0x1/}:W,duration_time
  Control descriptor is not initialized
  Warning:
  arb/event=0x84,umask=0x1/ event is not supported by the kernel.
  Error:
  The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (arb/event=0x84,umask=0x1/).
  /bin/dmesg | grep -i perf may provide additional information.
  
  [root@quaco ~]#

After:

  [root@quaco ~]# perf stat -M DRAM_BW_Use -- sleep 1
  
   Performance counter stats for 'system wide':
  
               2,806      arb/event=0x84,umask=0x1/ #     0.63 DRAM_BW_Use
          10,001,820      arb/event=0x81,umask=0x1/
       1,016,875,686 ns   duration_time
  
         1.016875686 seconds time elapsed
  
  [root@quaco ~]#

So I'm removing that fixes and adding this one, that I think is where
"duration_time" was being considered...

Fixes: e3ba76deef23064f ("perf tools: Force uncore events to system wide monitoring")

Also, wouldn't it be better to have the duration_time event with its
evsel->core.system_wide set to true?

- Arnaldo

Re: [PATCH] perf stat: Skip duration_time in setup_system_wide

[Jin, Yao]

Hi Arnaldo,

On 9/23/2020 2:02 AM, Arnaldo Carvalho de Melo wrote:
> Em Tue, Sep 22, 2020 at 02:56:30PM -0300, Arnaldo Carvalho de Melo escreveu:
>> Em Tue, Sep 22, 2020 at 09:50:04AM +0800, Jin Yao escreveu:
>>> Some metrics (such as DRAM_BW_Use) consists of uncore events and
>>> duration_time. For uncore events, counter->core.system_wide is
>>> true. But for duration_time, counter->core.system_wide is false
>>> so target.system_wide is set to false.
>>>
>>> Then 'enable_on_exec' is set in perf_event_attr of uncore event.
>>> Kernel will return error when trying to open the uncore event.
>>>
>>> This patch skips the duration_time in setup_system_wide then
>>> target.system_wide will be set to true for the evlist of uncore
>>> events + duration_time.
>>>
>>> Before (tested on skylake desktop):
>>>
>>>   # perf stat -M DRAM_BW_Use -- sleep 1
>>>   Error:
>>>   The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (arb/event=0x84,umask=0x1/).
>>>   /bin/dmesg | grep -i perf may provide additional information.
>>>
>>> After:
>>>
>>>   # perf stat -M DRAM_BW_Use -- sleep 1
>>>
>>>    Performance counter stats for 'system wide':
>>>
>>>                  169      arb/event=0x84,umask=0x1/ #     0.00 DRAM_BW_Use
>>>               40,427      arb/event=0x81,umask=0x1/
>>>        1,000,902,197 ns   duration_time
>>>
>>>          1.000902197 seconds time elapsed
>>>
>>> Fixes: 648b5af3f3ae ("libperf: Move 'system_wide' from 'struct evsel' to 'struct perf_evsel'")
>>
>> Humm, what makes you think that this cset was the one introducing this
>> problem? It just moves evsel->system_wide to evsel->core.system_wide.
> 
> Apart from that I reproduced the problem and after applying your patch
> it seems cured:
> 
>    [acme@quaco perf]$ grep 'model name' -m1 /proc/cpuinfo
>    model name	: Intel(R) Core(TM) i7-8650U CPU @ 1.90GHz
> 
> Before (with -v to see details):
> 
>    [root@quaco ~]# perf stat -v -M DRAM_BW_Use -- sleep 1
>    Using CPUID GenuineIntel-6-8E-A
>    metric expr 64 * ( arb@event\=0x81\,umask\=0x1@ + arb@event\=0x84\,umask\=0x1@ ) / 1000000 / duration_time / 1000 for DRAM_BW_Use
>    found event duration_time
>    found event arb/event=0x84,umask=0x1/
>    found event arb/event=0x81,umask=0x1/
>    adding {arb/event=0x84,umask=0x1/,arb/event=0x81,umask=0x1/}:W,duration_time
>    Control descriptor is not initialized
>    Warning:
>    arb/event=0x84,umask=0x1/ event is not supported by the kernel.
>    Error:
>    The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (arb/event=0x84,umask=0x1/).
>    /bin/dmesg | grep -i perf may provide additional information.
>    
>    [root@quaco ~]#
> 
> After:
> 
>    [root@quaco ~]# perf stat -M DRAM_BW_Use -- sleep 1
>    
>     Performance counter stats for 'system wide':
>    
>                 2,806      arb/event=0x84,umask=0x1/ #     0.63 DRAM_BW_Use
>            10,001,820      arb/event=0x81,umask=0x1/
>         1,016,875,686 ns   duration_time
>    
>           1.016875686 seconds time elapsed
>    
>    [root@quaco ~]#
> 
> So I'm removing that fixes and adding this one, that I think is where
> "duration_time" was being considered...
> 
> Fixes: e3ba76deef23064f ("perf tools: Force uncore events to system wide monitoring")
> 

Yes, this fixes is much better, thanks.

> Also, wouldn't it be better to have the duration_time event with its
> evsel->core.system_wide set to true?
> 

That looks to be another solution, should be OK too I think. :)

But anyway we need a test.

Thanks
Jin Yao

> - Arnaldo
>