Re: [PATCH v2] perf script: Fix overrun issue for dynamically-allocated pmu type number

[Jin, Yao]

Hi Arnaldo, Jiri,

On 12/25/2020 9:10 AM, Jin, Yao wrote:
> Hi Arnaldo, Jiri,
>
> On 12/11/2020 2:10 PM, Adrian Hunter wrote:
> > On 9/12/20 2:58 am, Jin Yao wrote:
> > > When unpacking the event which is from dynamic pmu, the array
> > > output[OUTPUT_TYPE_MAX] may be overrun. For example, type number of
> > > SKL uncore_imc is 10, but OUTPUT_TYPE_MAX is 7 now (OUTPUT_TYPE_MAX =
> > > PERF_TYPE_MAX + 1).
> > >
> > > /* In builtin-script.c */
> > > process_event()
> > > {
> > >          unsigned int type = output_type(attr->type);
> > >
> > >          if (output[type].fields == 0)
> > >                  return;
> > > }
> > >
> > > output[10] is overrun.
> > >
> > > Create a type OUTPUT_TYPE_OTHER for dynamic pmu events, then
> > > output_type(attr->type) will return OUTPUT_TYPE_OTHER here.
> > >
> > > Note that if PERF_TYPE_MAX ever changed, then there would be a conflict
> > > between old perf.data files that had a dynamicaliy allocated PMU number
> > > that would then be the same as a fixed PERF_TYPE.
> > >
> > > Example:
> > >
> > > perf record --switch-events -C 0 -e 
> > > "{cpu-clock,uncore_imc/data_reads/,uncore_imc/data_writes/}:SD" -a -- sleep 1
> > > perf script
> > >
> > > Before:
> > >           swapper     0 [000] 1479253.987551:     277766               cpu-clock:  
> > > ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
> > >           swapper     0 [000] 1479253.987797:     246709               cpu-clock:  
> > > ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
> > >           swapper     0 [000] 1479253.988127:     329883               cpu-clock:  
> > > ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
> > >           swapper     0 [000] 1479253.988273:     146393               cpu-clock:  
> > > ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
> > >           swapper     0 [000] 1479253.988523:     249977               cpu-clock:  
> > > ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
> > >           swapper     0 [000] 1479253.988877:     354090               cpu-clock:  
> > > ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
> > >           swapper     0 [000] 1479253.989023:     145940               cpu-clock:  
> > > ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
> > >           swapper     0 [000] 1479253.989383:     359856               cpu-clock:  
> > > ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
> > >           swapper     0 [000] 1479253.989523:     140082               cpu-clock:  
> > > ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
> > >
> > > After:
> > >           swapper     0 [000] 1397040.402011:     272384               cpu-clock:  
> > > ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
> > >           swapper     0 [000] 1397040.402011:       5396  uncore_imc/data_reads/:
> > >           swapper     0 [000] 1397040.402011:        967 uncore_imc/data_writes/:
> > >           swapper     0 [000] 1397040.402259:     249153               cpu-clock:  
> > > ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
> > >           swapper     0 [000] 1397040.402259:       7231  uncore_imc/data_reads/:
> > >           swapper     0 [000] 1397040.402259:       1297 uncore_imc/data_writes/:
> > >           swapper     0 [000] 1397040.402508:     249108               cpu-clock:  
> > > ffffffff9d4ddb6f cpuidle_enter_state+0xdf ([kernel.kallsyms])
> > >           swapper     0 [000] 1397040.402508:       5333  uncore_imc/data_reads/:
> > >           swapper     0 [000] 1397040.402508:       1008 uncore_imc/data_writes/:
> > >
> > > Signed-off-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
> >
> > Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
>
> Can this patch be accepted? :)
>
> Thanks
> Jin Yao

Can this bug fix be accepted or anything else I need to improve?

Thanks
Jin Yao