linux-kernel - Re: [PATCH 3/5] perf tools: Copy metric events properly when expand cgroups

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Message-ID: <20200923102256.GI2893484@krava>
Date:   Wed, 23 Sep 2020 12:22:56 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     Namhyung Kim <namhyung@...nel.org>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Stephane Eranian <eranian@...gle.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Ian Rogers <irogers@...gle.com>,
        John Garry <john.garry@...wei.com>,
        Kajol Jain <kjain@...ux.ibm.com>
Subject: Re: [PATCH 3/5] perf tools: Copy metric events properly when expand
 cgroups

On Wed, Sep 23, 2020 at 10:59:43AM +0900, Namhyung Kim wrote:

SNIP

  
> diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c
> index 8b6a4fa49082..dcd18ef268a1 100644
> --- a/tools/perf/util/cgroup.c
> +++ b/tools/perf/util/cgroup.c
> @@ -3,6 +3,9 @@
>  #include "evsel.h"
>  #include "cgroup.h"
>  #include "evlist.h"
> +#include "rblist.h"
> +#include "metricgroup.h"
> +#include "stat.h"
>  #include <linux/zalloc.h>
>  #include <sys/types.h>
>  #include <sys/stat.h>
> @@ -193,10 +196,12 @@ int parse_cgroups(const struct option *opt, const char *str,
>  	return 0;
>  }
>  
> -int evlist__expand_cgroup(struct evlist *evlist, const char *str)
> +int evlist__expand_cgroup(struct evlist *evlist, const char *str,
> +			  struct rblist *metric_events)
>  {
>  	struct evlist *orig_list, *tmp_list;
>  	struct evsel *pos, *evsel, *leader;
> +	struct rblist orig_metric_events;
>  	struct cgroup *cgrp = NULL;
>  	const char *p, *e, *eos = str + strlen(str);
>  	int ret = -1;
> @@ -216,6 +221,8 @@ int evlist__expand_cgroup(struct evlist *evlist, const char *str)
>  	/* save original events and init evlist */
>  	perf_evlist__splice_list_tail(orig_list, &evlist->core.entries);
>  	evlist->core.nr_entries = 0;
> +	orig_metric_events = *metric_events;
> +	rblist__init(metric_events);
>  
>  	for (;;) {
>  		p = strchr(str, ',');
> @@ -255,6 +262,11 @@ int evlist__expand_cgroup(struct evlist *evlist, const char *str)
>  		cgroup__put(cgrp);
>  		nr_cgroups++;
>  
> +		perf_stat__collect_metric_expr(tmp_list);

I know you added the option just for perf stat, not record,
but the code looks generic apart from using this function

I wonder if this would cause any issues if it was called in record
context.. maybe we could just skip it in that case, but that's for
future to worry about ;-)

jirka

> +		if (metricgroup__copy_metric_events(tmp_list, cgrp, metric_events,
> +						    &orig_metric_events) < 0)
> +			break;
> +
>  		perf_evlist__splice_list_tail(evlist, &tmp_list->core.entries);
>  		tmp_list->core.nr_entries = 0;
>  
> @@ -268,6 +280,7 @@ int evlist__expand_cgroup(struct evlist *evlist, const char *str)
>  out_err:
>  	evlist__delete(orig_list);
>  	evlist__delete(tmp_list);
> +	rblist__exit(&orig_metric_events);
>  
>  	return ret;
>  }

SNIP