Re: [RFC 00/13] perf_env/CPU socket reorg/fixes

[Wangnan (F)]

On 2015/9/11 21:36, Arnaldo Carvalho de Melo wrote:
> Em Fri, Sep 11, 2015 at 10:30:52AM -0300, Arnaldo Carvalho de Melo escreveu:
> > Em Fri, Sep 11, 2015 at 10:29:37AM -0300, Arnaldo Carvalho de Melo escreveu:
> > > Em Fri, Sep 11, 2015 at 10:03:39AM -0300, Arnaldo Carvalho de Melo escreveu:
> > > > Em Fri, Sep 11, 2015 at 08:20:54PM +0800, Wangnan (F) escreveu:
> > > > > I have tested patch 1 to 10. They looks good to me except patch 4/13. Please
> > > > Ok, I'll take that as a Tested-by: you for 1-10 with 4/13 having the
> > > > checks added, ok?
> > >   
> > > > > see my email in that thread.
> > >   
> > > > I add those checks.
> > > Ok, below is the diff for adding the checks. The get_{core,socket}_id
> > > functions should be moved to tools/lib/api/cpu.[ch], using the same
> > > interface as cpu__get_max_freq(&value), using the int return value to
> > > propagate the precise error, etc. Will do it in a follow up patch.
> > Humm, but then, what happens if a CPU is offline? I'm checking it now...
>    # cat /sys/devices/system/cpu/cpu3/topology/core_id
>    3
>    # cat
>    /sys/devices/system/cpu/cpu3/topology/physical_package_id
>    0
>    # echo 0 > /sys/devices/system/cpu/cpu3/online
>    # cat
>    /sys/devices/system/cpu/cpu3/topology/physical_package_id
>    cat: /sys/devices/system/cpu/cpu3/topology/physical_package_id: No such file or directory
>    # cat /sys/devices/system/cpu/cpu3/topology/core_id
>    cat: /sys/devices/system/cpu/cpu3/topology/core_id: No such file or directory
>    #
>
> So we shouldn't check the result, right? We could further validate it by
> checking:
>
>    # cat /sys/devices/system/cpu/cpu3/online
>    0
>    #
>
> But assuming that not being able to access it means it is offline looks
> almost reasonable, if not strictly correct, so I'm removing the tests
> and will revisit this when I move those functions to
> tools/lib/api/cpu.[ch].

I highly suspect that setting 'online' to 0 is not the only reason of
the removal of topology directory. Testing the existance of the two
files should be better.

Thank you.

> - Arnaldo
>
> > > diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
> > > index 6af4f7c36820..2e4cad84197b 100644
> > > --- a/tools/perf/util/env.c
> > > +++ b/tools/perf/util/env.c
> > > @@ -60,7 +60,7 @@ out_enomem:
> > >   
> > >   int perf_env__read_cpu_topology_map(struct perf_env *env)
> > >   {
> > > -	int cpu, nr_cpus;
> > > +	int cpu, nr_cpus, err;
> > >   
> > >   	if (env->cpu != NULL)
> > >   		return 0;
> > > @@ -77,10 +77,17 @@ int perf_env__read_cpu_topology_map(struct perf_env *env)
> > >   		return -ENOMEM;
> > >   
> > >   	for (cpu = 0; cpu < nr_cpus; ++cpu) {
> > > -		env->cpu[cpu].core_id	= cpu_map__get_core_id(cpu);
> > > -		env->cpu[cpu].socket_id	= cpu_map__get_socket_id(cpu);
> > > +		err = env->cpu[cpu].core_id = cpu_map__get_core_id(cpu);
> > > +		if (err < 0)
> > > +			goto out_free;
> > > +		err = env->cpu[cpu].socket_id = cpu_map__get_socket_id(cpu);
> > > +		if (err < 0)
> > > +			goto out_free;
> > >   	}
> > >   
> > > -	env->nr_cpus_avail = nr_cpus;
> > >   	return 0;
> > > +
> > > +out_free:
> > > +	zfree(&env->cpu);
> > > +	return err;
> > >   }


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