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

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Message-ID: <alpine.DEB.2.11.1602171934590.19512@nanos>
Date:	Wed, 17 Feb 2016 19:35:56 +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, Thomas Gleixner wrote:

> 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

And looking at rapl, it's the same trainwreck as uncore versus error
handling. Sigh....

Thanks,

	tglx