linux-kernel - Re: [tip:perfcounters/core] perf sched: Determine the number of CPUs automatically

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Date:	Thu, 17 Sep 2009 21:45:30 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Arjan van de Ven <arjan@...radead.org>
Cc:	mingo@...hat.com, hpa@...or.com, paulus@...ba.org, acme@...hat.com,
	linux-kernel@...r.kernel.org, fweisbec@...il.com,
	a.p.zijlstra@...llo.nl, efault@....de, tglx@...utronix.de,
	linux-tip-commits@...r.kernel.org
Subject: Re: [tip:perfcounters/core] perf sched: Determine the number of
	CPUs automatically


* Arjan van de Ven <arjan@...radead.org> wrote:

> On Thu, 17 Sep 2009 18:07:09 GMT
> > 
> > perf sched: Determine the number of CPUs automatically
> > 
> > For 'perf sched map' output, determine max_cpu automatically,
> > instead of the static default of 15.
> >  
> >  static u32 curr_pid[MAX_CPUS] = { [0 ... MAX_CPUS-1] = -1 };
> >  
> > @@ -1818,6 +1818,9 @@ static struct trace_sched_handler map_ops  = {
> >  
> >  static void __cmd_map(void)
> >  {
> > +	max_cpu = system("exit `grep ^processor /proc/cpuinfo  | wc
> > -l`");
> 
> YUCK.
> 
> what is wrong with
>    max_cpu = sysconf(_SC_NPROCESSORS_CONF); 
> ??

That's nicer - mind sending a patch?

	Ingo
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