linux-kernel - Re: [PATCH v5 0/5] perf stat: Support overall statistics for interval mode

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Message-ID: <104037dd-5e2e-a6fd-51ae-2e0a1cc2860a@linux.ibm.com>
Date:   Thu, 14 May 2020 15:23:17 +0530
From:   kajoljain <kjain@...ux.ibm.com>
To:     Jin Yao <yao.jin@...ux.intel.com>, acme@...nel.org,
        jolsa@...nel.org, peterz@...radead.org, mingo@...hat.com,
        alexander.shishkin@...ux.intel.com
Cc:     Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
        kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH v5 0/5] perf stat: Support overall statistics for interval
 mode



On 5/14/20 11:06 AM, Jin Yao wrote:
> Currently perf-stat supports to print counts at regular interval (-I),
> but it's not very easy for user to get the overall statistics.
> 
> With this patchset, it supports to report the summary at the end of
> interval output.
> 
> For example,
> 
>  root@...-ppc:~# perf stat -e cycles -I1000 --interval-count 2
>  #           time             counts unit events
>       1.000412064          2,281,114      cycles
>       2.001383658          2,547,880      cycles
> 
>   Performance counter stats for 'system wide':
> 
>           4,828,994      cycles
> 
>         2.002860349 seconds time elapsed
> 
>  root@...-ppc:~# perf stat -e cycles,instructions -I1000 --interval-count 2
>  #           time             counts unit events
>       1.000389902          1,536,093      cycles
>       1.000389902            420,226      instructions              #    0.27  insn per cycle
>       2.001433453          2,213,952      cycles
>       2.001433453            735,465      instructions              #    0.33  insn per cycle
> 
>   Performance counter stats for 'system wide':
> 
>           3,750,045      cycles
>           1,155,691      instructions              #    0.31  insn per cycle
> 
>         2.003023361 seconds time elapsed
> 
>  root@...-ppc:~# perf stat -M CPI,IPC -I1000 --interval-count 2
>  #           time             counts unit events
>       1.000435121            905,303      inst_retired.any          #      2.9 CPI
>       1.000435121          2,663,333      cycles
>       1.000435121            914,702      inst_retired.any          #      0.3 IPC
>       1.000435121          2,676,559      cpu_clk_unhalted.thread
>       2.001615941          1,951,092      inst_retired.any          #      1.8 CPI
>       2.001615941          3,551,357      cycles
>       2.001615941          1,950,837      inst_retired.any          #      0.5 IPC
>       2.001615941          3,551,044      cpu_clk_unhalted.thread
> 
>   Performance counter stats for 'system wide':
> 
>           2,856,395      inst_retired.any          #      2.2 CPI
>           6,214,690      cycles
>           2,865,539      inst_retired.any          #      0.5 IPC
>           6,227,603      cpu_clk_unhalted.thread
> 
>         2.003403078 seconds time elapsed

Hi Jin,
	Reporting the summary will be great for understanding overall stats. So, Before the
patch where we are reseting rt_stat before read_counters to make sure, whatever printing
in final aggregate is as per counts on that interval, 

we used to update stats->means and other info as described in 

RFC: https://lkml.org/lkml/2020/3/24/158

Now, stats->means is same as counts which we are using in generic_metric function. Is this expected behavior?
I am not sure, if data like stats->means and all suppose to update per interval or we are using it somewhere else.

So, As we call update_stats for each event and for each interval, can we somehow use that
to print overall stats maybe by adding some var in `struct stats` to keep count of total counts for that event.
Please let me know if my understanding is fine.

Thanks,
Kajol Jain


 
> 
>  v5:
>  ---
>  1. Create new patch "perf stat: Save aggr value to first member
>     of prev_raw_counts".
> 
>  2. Call perf_evlist__save_aggr_prev_raw_counts to save aggr value
>     to first member of prev_raw_counts for AGGR_GLOBAL. Then next,
>     perf_stat_process_counter can create aggr values from per cpu
>     values.
> 
>  Following patches are impacted in v5:
>     perf stat: Copy counts from prev_raw_counts to evsel->counts
>     perf stat: Save aggr value to first member of prev_raw_counts
>     perf stat: Report summary for interval mode
> 
>  v4:
>  ---
>  1. Create runtime_stat_reset.
> 
>  2. Zero the aggr in perf_counts__reset and use it to reset
>     prev_raw_counts.
> 
>  3. Move affinity setup and read_counter_cpu to a new function
>     read_affinity_counters. It's only called when stat_config.summary
>     is not set.
> 
>  v3:
>  ---
>  1. 'perf stat: Fix wrong per-thread runtime stat for interval mode'
>     is a new patch which fixes an existing issue found in test.
> 
>  2. We use the prev_raw_counts for summary counts. Drop the summary_counts in v2.
> 
>  3. Fix some issues.
> 
>  v2:
>  ---
>  Rebase to perf/core branch
> 
> Jin Yao (5):
>   perf stat: Fix wrong per-thread runtime stat for interval mode
>   perf counts: Reset prev_raw_counts counts
>   perf stat: Copy counts from prev_raw_counts to evsel->counts
>   perf stat: Save aggr value to first member of prev_raw_counts
>   perf stat: Report summary for interval mode
> 
>  tools/perf/builtin-stat.c | 101 ++++++++++++++++++++++++++------------
>  tools/perf/util/counts.c  |   4 +-
>  tools/perf/util/counts.h  |   1 +
>  tools/perf/util/stat.c    |  43 +++++++++++++---
>  tools/perf/util/stat.h    |   3 ++
>  5 files changed, 113 insertions(+), 39 deletions(-)
>