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Date: Thu, 14 May 2020 21:44:50 +0800
From: "Jin, Yao" <yao.jin@...ux.intel.com>
To: kajoljain <kjain@...ux.ibm.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
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@...-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,
>
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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