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From: Marc Zyngier <marc.zyngier@arm.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>
Cc: Waiman Long <longman@redhat.com>,
	Matthew Wilcox <willy@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Alexey Dobriyan <adobriyan@gmail.com>,
	Kees Cook <keescook@chromium.org>,
	linux-fsdevel@vger.kernel.org,
	Davidlohr Bueso <dave@stgolabs.net>,
	Miklos Szeredi <miklos@szeredi.hu>,
	Daniel Colascione <dancol@google.com>,
	Dave Chinner <david@fromorbit.com>,
	Randy Dunlap <rdunlap@infradead.org>
Subject: Re: [patch V2 0/2] genirq, proc: Speedup /proc/stat interrupt statistics
Date: Fri, 8 Feb 2019 17:40:30 +0000
Message-ID: <0a0ad274-83fb-8310-a306-68aa65eeef63@arm.com> (raw)
In-Reply-To: <20190208134802.218483159@linutronix.de>

On 08/02/2019 13:48, Thomas Gleixner wrote:
> Waiman reported that on large systems with a large amount of interrupts the
> readout of /proc/stat takes a long time to sum up the interrupt
> statistics. In principle this is not a problem. but for unknown reasons
> some enterprise quality software reads /proc/stat with a high frequency.
> 
> The reason for this is that interrupt statistics are accounted per cpu. So
> the /proc/stat logic has to sum up the interrupt stats for each interrupt.
> 
> The following series addresses this by making the interrupt statitics code
> in the core generate the sum directly and by making the loop in the
> /proc/stat read function smarter.
> 
> V1 -> V2: Address review feedback: undo struct layout changes, make
>       	  variables unsigned and add test results to the changelog.
> 
> Thanks,
> 
>         tglx
> 
> 8<----------------
>  fs/proc/stat.c          |   29 ++++++++++++++++++++++++++---
>  include/linux/irqdesc.h |    1 +
>  kernel/irq/chip.c       |   12 ++++++++++--
>  kernel/irq/internals.h  |    8 +++++++-
>  kernel/irq/irqdesc.c    |    7 ++++++-
>  5 files changed, 50 insertions(+), 7 deletions(-)
> 

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

      parent reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-08 13:48 Thomas Gleixner
2019-02-08 13:48 ` [patch V2 1/2] genriq: Avoid summation loops for /proc/stat Thomas Gleixner
2019-02-08 22:32   ` Andrew Morton
2019-02-08 22:46     ` Waiman Long
2019-02-08 23:21       ` Andrew Morton
2019-02-09  3:41         ` Matthew Wilcox
2019-02-13 15:55           ` David Laight
2019-02-08 13:48 ` [patch V2 2/2] proc/stat: Make the interrupt statistics more efficient Thomas Gleixner
2019-02-08 17:01   ` Alexey Dobriyan
2019-02-08 15:20 ` [patch V2 0/2] genirq, proc: Speedup /proc/stat interrupt statistics Waiman Long
2019-02-08 17:01 ` Davidlohr Bueso
2019-02-08 17:40 ` Marc Zyngier [this message]

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