linux-kernel - Re: [PATCH] x86/perf/intel/cqm: Get rid of the silly for_each

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Message-ID: <alpine.DEB.2.11.1602171929210.19512@nanos>
Date:	Wed, 17 Feb 2016 19:31:01 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Vikas Shivappa <vikas.shivappa@...el.com>
cc:	LKML <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>, x86@...nel.org,
	Stephane Eranian <eranian@...gle.com>,
	Matt Fleming <matt@...eblueprint.co.uk>
Subject: Re: [PATCH] x86/perf/intel/cqm: Get rid of the silly for_each_cpu
 lookups

On Wed, 17 Feb 2016, Vikas Shivappa wrote:
> > -	cpumask_set_cpu(cpu, &cqm_cpumask);
> > +	/* First online cpu in package becomes the reader */
> > +	reader = cpumask_any_and(topology_core_cpumask(cpu), &cqm_cpumask);
> > +	if (reader >= nr_cpu_ids)
> > +		cpumask_set_cpu(cpu, &cqm_cpumask);
> 
> I was confused by the topology_core_cpumask naming as its really the mask of
> all cpus in the same package. I sent a patch for cqm and rapl to fix this
> looping when you had given the same feedback during CAt patches review , but
> they have never made it so far due to CAT patch issues.

Duh, totally forgot about them.
 
> Would it be better to resend the rapl (looks like perf_uncore has same loop)
> fixes separately ?

Yes, please resend the rapl one. perf_uncore is a different trainwreck which I
fixed already:

      lkml.kernel.org/r/20160217132903.767990400@...utronix.de

Thanks,

	tglx