RE: [PATCH v4] tools/perf/metricgroup: Fix printing event names of metric group with multiple events incase of overlapping events

[Joakim Zhang]

> -----Original Message-----
> From: kajoljain <kjain@xxxxxxxxxxxxx>
> Sent: 2020年2月20日 17:54
> To: Joakim Zhang <qiangqing.zhang@xxxxxxx>; acme@xxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-perf-users@xxxxxxxxxxxxxxx; Jiri Olsa
> <jolsa@xxxxxxxxxx>; Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>;
> Andi Kleen <ak@xxxxxxxxxxxxxxx>; Kan Liang <kan.liang@xxxxxxxxxxxxxxx>; Peter
> Zijlstra <peterz@xxxxxxxxxxxxx>; Jin Yao <yao.jin@xxxxxxxxxxxxxxx>; Madhavan
> Srinivasan <maddy@xxxxxxxxxxxxxxxxxx>; Anju T Sudhakar
> <anju@xxxxxxxxxxxxxxxxxx>; Ravi Bangoria <ravi.bangoria@xxxxxxxxxxxxx>
> Subject: Re: [PATCH v4] tools/perf/metricgroup: Fix printing event names of
> metric group with multiple events incase of overlapping events
> 
> 
> 
> On 2/17/20 8:41 AM, Joakim Zhang wrote:
> >
> >> -----Original Message-----
> >> From: linux-perf-users-owner@xxxxxxxxxxxxxxx
> >> <linux-perf-users-owner@xxxxxxxxxxxxxxx> On Behalf Of Kajol Jain
> >> Sent: 2020年2月12日 13:41
> >> To: acme@xxxxxxxxxx
> >> Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-perf-users@xxxxxxxxxxxxxxx;
> >> kjain@xxxxxxxxxxxxx; Jiri Olsa <jolsa@xxxxxxxxxx>; Alexander Shishkin
> >> <alexander.shishkin@xxxxxxxxxxxxxxx>; Andi Kleen
> >> <ak@xxxxxxxxxxxxxxx>; Kan Liang <kan.liang@xxxxxxxxxxxxxxx>; Peter
> >> Zijlstra <peterz@xxxxxxxxxxxxx>; Jin Yao <yao.jin@xxxxxxxxxxxxxxx>;
> >> Madhavan Srinivasan <maddy@xxxxxxxxxxxxxxxxxx>; Anju T Sudhakar
> >> <anju@xxxxxxxxxxxxxxxxxx>; Ravi Bangoria
> >> <ravi.bangoria@xxxxxxxxxxxxx>
> >> Subject: [PATCH v4] tools/perf/metricgroup: Fix printing event names
> >> of metric group with multiple events incase of overlapping events
> >>
> >> 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@xxxxxxxxxxxxx>
> >> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> >> Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
> >> Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> >> Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
> >> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> >> Cc: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
> >> Cc: Madhavan Srinivasan <maddy@xxxxxxxxxxxxxxxxxx>
> >> Cc: Anju T Sudhakar <anju@xxxxxxxxxxxxxxxxxx>
> >> Cc: Ravi Bangoria <ravi.bangoria@xxxxxxxxxxxxx>
> >> ---
> >>  tools/perf/util/metricgroup.c | 50
> >> ++++++++++++++++++++++-------------
> >>  1 file changed, 31 insertions(+), 19 deletions(-)
> >
> > Hi Kajol,
> >
> > I am not sure if it is good to ask a question here :-)
> >
> > I encountered a perf metricgroup issue, the result is incorrect when the
> metric includes more than 2 events.
> >
> > git log --oneline tools/perf/util/metricgroup.c
> > 3635b27cc058 perf metricgroup: Fix printing event names of metric
> > group with multiple events f01642e4912b perf metricgroup: Support
> > multiple events for metricgroup
> > 287f2649f791 perf metricgroup: Scale the metric result
> >
> > I did a simple test, below is the JSON file and result.
> > [
> >         {
> >              "PublicDescription": "Calculate DDR0 bus actual utilization
> which vary from DDR0 controller clock frequency",
> >              "BriefDescription": "imx8qm: ddr0 bus actual utilization",
> >              "MetricName": "imx8qm-ddr0-bus-util",
> >              "MetricExpr": "( imx8_ddr0\\/read\\-cycles\\/ +
> imx8_ddr0\\/write\\-cycles\\/ )",
> >              "MetricGroup": "i.MX8QM_DDR0_BUS_UTIL"
> >         }
> > ]
> > ./perf stat -I 1000 -M imx8qm-ddr0-bus-util
> > #           time             counts unit events
> >      1.000104250              16720      imx8_ddr0/read-cycles/
> #  22921.0 imx8qm-ddr0-bus-util
> >      1.000104250               6201      imx8_ddr0/write-cycles/
> >      2.000525625               8316      imx8_ddr0/read-cycles/
> #  12785.5 imx8qm-ddr0-bus-util
> >      2.000525625               2738      imx8_ddr0/write-cycles/
> >      3.000819125               1056      imx8_ddr0/read-cycles/
> #   4136.7 imx8qm-ddr0-bus-util
> >      3.000819125                303      imx8_ddr0/write-cycles/
> >      4.001103750               6260      imx8_ddr0/read-cycles/
> #   9149.8 imx8qm-ddr0-bus-util
> >      4.001103750               2317      imx8_ddr0/write-cycles/
> >      5.001392750               2084      imx8_ddr0/read-cycles/
> #   4516.0 imx8qm-ddr0-bus-util
> >      5.001392750                601      imx8_ddr0/write-cycles/
> >
> > You can see that only the first result is correct, could this be reproduced at
> you side?
> 
> Hi Joakim,
>         Will try to look into it from my side.


Thanks Kajol for your help, I look into this issue, but don't know how to fix it.

The results are always correct if signal event used in "MetricExpr" with "-I" parameters, but the results are incorrect when more than one events used in "MetricExpr".

Hope you can find the root cause :-)

Best Regards,
Joakim Zhang
> Thanks,
> Kajol
> >
> > Thanks a lot!
> >
> > Best Regards,
> > Joakim Zhang
> >