From: Peter Zijlstra <peterz@infradead.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Li RongQing <lirongqing@baidu.com>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] genirq: only scan the present CPUs
Date: Tue, 3 Apr 2018 13:23:11 +0200 [thread overview]
Message-ID: <20180403112311.GF4043@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <alpine.DEB.2.21.1804031224150.2511@nanos.tec.linutronix.de>
On Tue, Apr 03, 2018 at 12:25:56PM +0200, Thomas Gleixner wrote:
> On Mon, 2 Apr 2018, Li RongQing wrote:
>
> > lots of application will read /proc/stat, like ps and vmstat, but we
> > find the reading time are spreading on Purley platform which has lots
> > of possible CPUs and interrupt.
> >
> > To reduce the reading time, only scan the present CPUs, not all possible
> > CPUs, which speeds the reading of /proc/stat 20 times on Purley platform
> > which has 56 present CPUs, and 224 possible CPUs
>
> Why is BIOS/ACPI telling the kernel that there are 224 possible CPUs unless
> it supports physical CPU hotplug.
BIOS is crap, news at 11. I've got boxes like that too. Use
possible_cpu=$nr if you're bothered by it -- it's what I do.
next prev parent reply other threads:[~2018-04-03 11:23 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-02 5:45 Li RongQing
2018-04-03 10:25 ` Thomas Gleixner
2018-04-03 11:23 ` Peter Zijlstra [this message]
2018-04-06 8:42 ` Dou Liyang
2018-04-06 9:02 ` Peter Zijlstra
2018-04-06 9:05 ` Peter Zijlstra
2018-04-09 6:33 ` Dou Liyang
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