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    SubjectRe: [PATCH v5 0/5] perf stat: Support overall statistics for interval mode
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    Hi Kajoljain,

    On 5/14/2020 5:53 PM, kajoljain wrote:
    >
    >
    > 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,
    >

    Yes, I had similar thoughts, so I posted following patch.

    https://lore.kernel.org/lkml/20200420145417.6864-1-yao.jin@linux.intel.com/

    > we used to update stats->means and other info as described in
    >
    > RFC: https://lkml.org/lkml/2020/3/24/158
    >

    I've checked your patch but sorry I'm also not very sure if it's the expected
    behavior.

    > 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.
    >

    I just think it's easy to understand, that is the metric calculated by the
    counts per interval.

    > 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.
    >

    Adding var in 'struct stats' looks not enough (or more complicated), because
    perf-stat also needs to report some counts according to different aggregation
    modes (not only the metric). I just think copying total counts to current counts
    is a easy way because we can reuse most of existing non-interval processing code.

    Thanks
    Jin Yao

    > 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(-)
    >>

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