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Date: Tue, 24 Apr 2018 09:18:59 +0300
From: Alexey Dobriyan <adobriyan@gmail.com>
To: David Rientjes <rientjes@google.com>
Cc: "Joel Fernandes (Google)" <joel.opensrc@gmail.com>,
        Waiman Long <longman@redhat.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        rdunlap@infradead.org, Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] proc/stat: Separate out individual irq counts into
 /proc/stat_irqs
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On Mon, Apr 23, 2018 at 10:54:18PM -0700, David Rientjes wrote:
> On Sat, 21 Apr 2018, Alexey Dobriyan wrote:
> 
> > > On Thu, Apr 19, 2018 at 04:23:02PM -0700, Joel Fernandes (Google) wrote:
> > > > Can we not just remove per-IRQ stats from /proc/stat (since I gather
> > > > from this discussion it isn't scalable), and just have applications
> > > > that need per-IRQ stats use /proc/interrupts ?
> > > 
> > > If you can prove noone is using them in /proc/stat...
> > 
> > And you can't even stick WARN into /proc/stat to find out.
> > 
> 
> FWIW, removing per irq counts from /proc/stat would break some of our
> scripts.  We could adapt to that, but everybody else would have to as
> well, so I'm afraid it's not going to be possible.

Excellent!

> It would probably be better to extract out the stats that you're actually
> interested in to a new file.

This is the worst scenario. Individual IRQ stats are going to live in 2 places.
And /proc/stat still would be slow.