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

From: kajoljain
Date: Thu May 14 2020 - 05:53:36 EST




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@kbl-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@kbl-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@kbl-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(-)
>