linux-kernel - Re: [PATCH 2/3] perf tools: Add perf_env__numa

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Date:   Mon, 2 Sep 2019 16:16:47 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Jiri Olsa <jolsa@...nel.org>, lkml <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Michael Petlan <mpetlan@...hat.com>,
        Joe Mario <jmario@...hat.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Andi Kleen <ak@...ux.intel.com>
Subject: Re: [PATCH 2/3] perf tools: Add perf_env__numa_node function

On Mon, Sep 02, 2019 at 10:57:10AM -0300, Arnaldo Carvalho de Melo wrote:
> Em Mon, Sep 02, 2019 at 02:12:54PM +0200, Jiri Olsa escreveu:
> > To speed up cpu to node lookup, adding perf_env__numa_node
> > function, that creates cpu array on the first lookup, that
> > holds numa nodes for each stored cpu.
> > 
> > Link: http://lkml.kernel.org/n/tip-qqwxklhissf3yjyuaszh6480@git.kernel.org
> > Signed-off-by: Jiri Olsa <jolsa@...nel.org>
> > ---
> >  tools/perf/util/env.c | 35 +++++++++++++++++++++++++++++++++++
> >  tools/perf/util/env.h |  6 ++++++
> >  2 files changed, 41 insertions(+)
> > 
> > diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
> > index 3baca06786fb..6385961e45df 100644
> > --- a/tools/perf/util/env.c
> > +++ b/tools/perf/util/env.c
> > @@ -179,6 +179,7 @@ void perf_env__exit(struct perf_env *env)
> >  	zfree(&env->sibling_threads);
> >  	zfree(&env->pmu_mappings);
> >  	zfree(&env->cpu);
> > +	zfree(&env->numa_map);
> >  
> >  	for (i = 0; i < env->nr_numa_nodes; i++)
> >  		perf_cpu_map__put(env->numa_nodes[i].map);
> > @@ -338,3 +339,37 @@ const char *perf_env__arch(struct perf_env *env)
> >  
> >  	return normalize_arch(arch_name);
> >  }
> > +
> > +
> > +int perf_env__numa_node(struct perf_env *env, int cpu)
> > +{
> > +	if (!env->nr_numa_map) {
> > +		struct numa_node *nn;
> > +		int i, nr = 0;
> > +
> > +		for (i = 0; i < env->nr_numa_nodes; i++) {
> > +			nn = &env->numa_nodes[i];
> > +			nr = max(nr, perf_cpu_map__max(nn->map));
> > +		}
> > +
> > +		nr++;
> > +		env->numa_map = zalloc(nr * sizeof(int));
> 
> Why do you use zalloc()...
> 
> > +		if (!env->numa_map)
> > +			return -1;
> 
> Only to right after allocating it set all entries to -1?
> 
> That zalloc() should be downgraded to a plain malloc(), right?
> 
> The setting to -1 is because we may have holes in the array, right? I
> think this deserves a comment here as well.

yea, I added that later on and missed the zalloc above ;-)

I'll send new version

thanks,
jirka