RE: [PATCH] perf metricgroup: Fix system PMU metrics

[Joakim Zhang]

> -----Original Message-----
> From: John Garry <john.garry@xxxxxxxxxx>
> Sent: 2021年1月19日 18:04
> To: peterz@xxxxxxxxxxxxx; mingo@xxxxxxxxxx; acme@xxxxxxxxxx;
> mark.rutland@xxxxxxx; alexander.shishkin@xxxxxxxxxxxxxxx;
> jolsa@xxxxxxxxxx; namhyung@xxxxxxxxxx; irogers@xxxxxxxxxx;
> kjain@xxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx; linuxarm@xxxxxxxxxxxxx; Joakim Zhang
> <qiangqing.zhang@xxxxxxx>; John Garry <john.garry@xxxxxxxxxx>
> Subject: [PATCH] perf metricgroup: Fix system PMU metrics
> 
> Joakim reports that getting "perf stat" for multiple system PMU metrics
> segfaults:
> ./perf stat -a -I 1000 -M imx8mm_ddr_write.all,imx8mm_ddr_write.all
> Segmentation fault
> 
> While the same works without issue for a single metric.
> 
> The logic in metricgroup__add_metric_sys_event_iter() is broken, in that
> add_metric() @m argument should be NULL for each new metric. Fix by not
> passing a holder for that, and rather make local in
> metricgroup__add_metric_sys_event_iter().
> 
> Fixes: be335ec28efa ("perf metricgroup: Support adding metrics for system
> PMUs")
> Reported-by: Joakim Zhang <qiangqing.zhang@xxxxxxx>
> Signed-off-by: John Garry <john.garry@xxxxxxxxxx>

root@imx8mmevk:~# ./perf stat -a -I 1000 -M imx8mm_ddr_read.all,imx8mm_ddr_write                                                                                                    .all
#           time             counts unit events
     1.001446500              40832      imx8mm_ddr.read_cycles    #    638.0 KB  imx8mm_ddr_read.all
     1.001446500              16973      imx8mm_ddr.write_cycles   #    265.2 KB  imx8mm_ddr_write.all
     2.003150250              28836      imx8mm_ddr.read_cycles    #    450.6 KB  imx8mm_ddr_read.all
     2.003150250               6705      imx8mm_ddr.write_cycles   #    104.8 KB  imx8mm_ddr_write.all

For this issue, Tested-by: Joakim Zhang <qiangqing.zhang@xxxxxxx>

Hi John,

It seems have other issue compared to 5.10 kernel after switching to this framework, below metric can't work.
"MetricExpr": "(( imx8_ddr0@read\\-cycles@ + imx8_ddr0@write\\-cycles@ ) * 4 * 4 / duration_time) / (750 * 1000000 * 4 * 4)"
After change to:
"MetricExpr": "(( imx8mm_ddr.read_cycles + imx8mm_ddr.write_cycles ) * 4 * 4 / duration_time) / (750 * 1000000 * 4 * 4)",


Best Regards,
Joakim Zhang
> diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c index
> ee94d3e8dd65..2e60ee170abc 100644
> --- a/tools/perf/util/metricgroup.c
> +++ b/tools/perf/util/metricgroup.c
> @@ -766,7 +766,6 @@ int __weak arch_get_runtimeparam(struct pmu_event
> *pe __maybe_unused)  struct metricgroup_add_iter_data {
>  	struct list_head *metric_list;
>  	const char *metric;
> -	struct metric **m;
>  	struct expr_ids *ids;
>  	int *ret;
>  	bool *has_match;
> @@ -1058,12 +1057,13 @@ static int
> metricgroup__add_metric_sys_event_iter(struct pmu_event *pe,
>  						  void *data)
>  {
>  	struct metricgroup_add_iter_data *d = data;
> +	struct metric *m = NULL;
>  	int ret;
> 
>  	if (!match_pe_metric(pe, d->metric))
>  		return 0;
> 
> -	ret = add_metric(d->metric_list, pe, d->metric_no_group, d->m, NULL,
> d->ids);
> +	ret = add_metric(d->metric_list, pe, d->metric_no_group, &m, NULL,
> +d->ids);
>  	if (ret)
>  		return ret;
> 
> @@ -1114,7 +1114,6 @@ static int metricgroup__add_metric(const char
> *metric, bool metric_no_group,
>  				.metric_list = &list,
>  				.metric = metric,
>  				.metric_no_group = metric_no_group,
> -				.m = &m,
>  				.ids = &ids,
>  				.has_match = &has_match,
>  				.ret = &ret,
> --
> 2.26.2