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Date: Fri, 20 Mar 2020 12:14:36 +0530
From: kajoljain <kjain@...ux.ibm.com>
To: Arnaldo Carvalho de Melo <arnaldo.melo@...il.com>
Cc: linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
Jiri Olsa <jolsa@...nel.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Andi Kleen <ak@...ux.intel.com>,
Kan Liang <kan.liang@...ux.intel.com>,
Peter Zijlstra <peterz@...radead.org>,
Jin Yao <yao.jin@...ux.intel.com>,
Madhavan Srinivasan <maddy@...ux.vnet.ibm.com>,
Anju T Sudhakar <anju@...ux.vnet.ibm.com>,
Ravi Bangoria <ravi.bangoria@...ux.ibm.com>
Subject: Re: [PATCH v6] tools/perf/metricgroup: Fix printing event names of
metric group with multiple events incase of overlapping events
On 3/19/20 12:58 AM, Arnaldo Carvalho de Melo wrote:
> Em Fri, Feb 21, 2020 at 03:41:21PM +0530, Kajol Jain escreveu:
>> Commit f01642e4912b ("perf metricgroup: Support multiple
>> events for metricgroup") introduced support for multiple events
>> in a metric group. But with the current upstream, metric events
>> names are not printed properly incase we try to run multiple
>> metric groups with overlapping event.
>>
>> With current upstream version, incase of overlapping metric events
>> issue is, we always start our comparision logic from start.
>> So, the events which already matched with some metric group also
>> take part in comparision logic. Because of that when we have overlapping
>> events, we end up matching current metric group event with already matched
>> one.
>>
>> For example, in skylake machine we have metric event CoreIPC and
>> Instructions. Both of them need 'inst_retired.any' event value.
>> As events in Instructions is subset of events in CoreIPC, they
>> endup in pointing to same 'inst_retired.any' value.
>>
>> In skylake platform:
>>
>> command:# ./perf stat -M CoreIPC,Instructions -C 0 sleep 1
>>
>> Performance counter stats for 'CPU(s) 0':
>>
>> 1,254,992,790 inst_retired.any # 1254992790.0
>> Instructions
>> # 1.3 CoreIPC
>> 977,172,805 cycles
>> 1,254,992,756 inst_retired.any
>>
>> 1.000802596 seconds time elapsed
>>
>> command:# sudo ./perf stat -M UPI,IPC sleep 1
>>
>> Performance counter stats for 'sleep 1':
>> 948,650 uops_retired.retire_slots
>> 866,182 inst_retired.any # 0.7 IPC
>> 866,182 inst_retired.any
>> 1,175,671 cpu_clk_unhalted.thread
>>
>> Patch fixes the issue by adding a new bool pointer 'evlist_used' to keep
>> track of events which already matched with some group by setting it true.
>> So, we skip all used events in list when we start comparision logic.
>> Patch also make some changes in comparision logic, incase we get a match
>> miss, we discard the whole match and start again with first event id in
>> metric event.
>>
>> With this patch:
>> In skylake platform:
>>
>> command:# ./perf stat -M CoreIPC,Instructions -C 0 sleep 1
>>
>> Performance counter stats for 'CPU(s) 0':
>>
>> 3,348,415 inst_retired.any # 0.3 CoreIPC
>> 11,779,026 cycles
>> 3,348,381 inst_retired.any # 3348381.0
>> Instructions
>>
>> 1.001649056 seconds time elapsed
>>
>> command:# ./perf stat -M UPI,IPC sleep 1
>>
>> Performance counter stats for 'sleep 1':
>>
>> 1,023,148 uops_retired.retire_slots # 1.1 UPI
>> 924,976 inst_retired.any
>> 924,976 inst_retired.any # 0.6 IPC
>> 1,489,414 cpu_clk_unhalted.thread
>>
>> 1.003064672 seconds time elapsed
>>
>> Signed-off-by: Kajol Jain <kjain@...ux.ibm.com>
>> Acked-by: Jiri Olsa <jolsa@...nel.org>
>
> This is an area I think needs some improvement, look how it ends up
> setting up the inst_retired.any multiple times:
>
> [root@...enth ~]# perf stat -vv -M CoreIPC,Instructions -C 0 sleep 1
> Using CPUID GenuineIntel-6-9E-9
> metric expr inst_retired.any / cycles for CoreIPC
> found event inst_retired.any
> found event cycles
> metric expr inst_retired.any for Instructions
> found event inst_retired.any
> adding {inst_retired.any,cycles}:W,{inst_retired.any}:W
> intel_pt default config: tsc,mtc,mtc_period=3,psb_period=3,pt,branch
> inst_retired.any -> cpu/event=0xc0,(null)=0x1e8483/
> inst_retired.any -> cpu/event=0xc0,(null)=0x1e8483/
> ------------------------------------------------------------
> perf_event_attr:
> type 4
> size 120
> config 0xc0
> sample_type IDENTIFIER
> read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING|ID|GROUP
> disabled 1
> inherit 1
> exclude_guest 1
> ------------------------------------------------------------
> sys_perf_event_open: pid -1 cpu 0 group_fd -1 flags 0x8 = 3
> ------------------------------------------------------------
> perf_event_attr:
> size 120
> sample_type IDENTIFIER
> read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING|ID|GROUP
> inherit 1
> exclude_guest 1
> ------------------------------------------------------------
> sys_perf_event_open: pid -1 cpu 0 group_fd 3 flags 0x8 = 4
> ------------------------------------------------------------
> perf_event_attr:
> type 4
> size 120
> config 0xc0
> sample_type IDENTIFIER
> read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
> disabled 1
> inherit 1
> exclude_guest 1
> ------------------------------------------------------------
> sys_perf_event_open: pid -1 cpu 0 group_fd -1 flags 0x8 = 5
> inst_retired.any: 0: 507070 1000948076 1000948076
> cycles: 0: 1250258 1000948076 1000948076
> inst_retired.any: 0: 507038 1000953052 1000953052
> inst_retired.any: 507070 1000948076 1000948076
> cycles: 1250258 1000948076 1000948076
> inst_retired.any: 507038 1000953052 1000953052
>
> Performance counter stats for 'CPU(s) 0':
>
> 507,070 inst_retired.any # 0.4 CoreIPC
> 1,250,258 cycles
> 507,038 inst_retired.any # 507038.0 Instructions
>
> 1.000964961 seconds time elapsed
>
> [root@...enth ~]#
>
> And it ends up printing the "inst_retired.any" multiple times, with
> different values, as after all two events were allocated, can't we
> notice this and set just one inst_retired.any and then when calculating
> the metrics just do something like:
>
> # perf stat -M CoreIPC,Instructions -C 0 sleep 1
>
> Performance counter stats for 'CPU(s) 0':
>
> 507,070 inst_retired.any # 0.4 CoreIPC,
> # 507,070 Instructions
> 1,250,258 cycles
>
> 1.000964961 seconds time elapsed
> #
>
> ?
>
> Ditto for:
>
> command:# perf stat -M UPI,IPC sleep 1
>
> Performance counter stats for 'sleep 1':
>
> 1,023,148 uops_retired.retire_slots # 1.1 UPI
> 924,976 inst_retired.any
> 924,976 inst_retired.any # 0.6 IPC
> 1,489,414 cpu_clk_unhalted.thread
>
> 1.003064672 seconds time elapsed
>
> Wouldn't this be better as:
>
> command:# perf stat -M UPI,IPC sleep 1
>
> Performance counter stats for 'sleep 1':
>
> 1,023,148 uops_retired.retire_slots # 1.1 UPI
> 924,976 inst_retired.any
> 1,489,414 cpu_clk_unhalted.thread # 0.6 IPC
>
> 1.003064672 seconds time elapsed
>
> This should help to look at many metrics at the same time by requiring
> less counters to be allocated, etc, or am I missing something here?
Hi Arnaldo,
Yes that will be better. I will look into it from my end.
Thanks,
Kajol
>
> Since this went thru multiple versions and Jiri is satisfied with it,
> I'm applying the patch, but please consider this suggestion.
>
> - Arnaldo
>
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