From: Stefan Priebe - Profihost AG <s.priebe@profihost.ag>
To: Zhu Yanhai <zhu.yanhai@gmail.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>,
Pekka Enberg <penberg@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mel@csn.ul.ie>, Jens Axboe <jaxboe@fusionio.com>,
Linux Netdev List <netdev@vger.kernel.org>
Subject: Re: slow performance on disk/network i/o full speed after drop_caches
Date: Wed, 31 Aug 2011 09:11:02 +0200 [thread overview]
Message-ID: <4E5DDE86.3040202@profihost.ag> (raw)
In-Reply-To: <4E573A99.4060309@profihost.ag>
Hi Fengguang,
Hi Yanhai,
> you're abssolutely corect zone_reclaim_mode is on - but why?
> There must be some linux software which switches it on.
>
> ~# grep 'zone_reclaim_mode' /etc/sysctl.* -r -i
> ~#
>
> also
> ~# grep 'zone_reclaim_mode' /etc/sysctl.* -r -i
> ~#
>
> tells us nothing.
>
> I've then read this:
>
> "zone_reclaim_mode is set during bootup to 1 if it is determined that
> pages from remote zones will cause a measurable performance reduction.
> The page allocator will then reclaim easily reusable pages (those page
> cache pages that are currently not used) before allocating off node pages."
>
> Why does the kernel do that here in our case on these machines.
Can nobody help why the kernel in this case set it to 1?
Stefan
WARNING: multiple messages have this Message-ID (diff)
From: Stefan Priebe - Profihost AG <s.priebe@profihost.ag>
To: Zhu Yanhai <zhu.yanhai@gmail.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>,
Pekka Enberg <penberg@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mel@csn.ul.ie>, Jens Axboe <jaxboe@fusionio.com>,
Linux Netdev List <netdev@vger.kernel.org>
Subject: Re: slow performance on disk/network i/o full speed after drop_caches
Date: Wed, 31 Aug 2011 09:11:02 +0200 [thread overview]
Message-ID: <4E5DDE86.3040202@profihost.ag> (raw)
In-Reply-To: <4E573A99.4060309@profihost.ag>
Hi Fengguang,
Hi Yanhai,
> you're abssolutely corect zone_reclaim_mode is on - but why?
> There must be some linux software which switches it on.
>
> ~# grep 'zone_reclaim_mode' /etc/sysctl.* -r -i
> ~#
>
> also
> ~# grep 'zone_reclaim_mode' /etc/sysctl.* -r -i
> ~#
>
> tells us nothing.
>
> I've then read this:
>
> "zone_reclaim_mode is set during bootup to 1 if it is determined that
> pages from remote zones will cause a measurable performance reduction.
> The page allocator will then reclaim easily reusable pages (those page
> cache pages that are currently not used) before allocating off node pages."
>
> Why does the kernel do that here in our case on these machines.
Can nobody help why the kernel in this case set it to 1?
Stefan
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next prev parent reply other threads:[~2011-08-31 7:11 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-24 6:06 slow performance on disk/network i/o full speed after drop_caches Stefan Priebe - Profihost AG
2011-08-24 6:20 ` Pekka Enberg
2011-08-24 6:20 ` Pekka Enberg
2011-08-24 9:01 ` Stefan Priebe - Profihost AG
2011-08-24 9:01 ` Stefan Priebe - Profihost AG
2011-08-24 9:33 ` Wu Fengguang
2011-08-24 9:33 ` Wu Fengguang
2011-08-25 9:00 ` Stefan Priebe - Profihost AG
2011-08-25 9:00 ` Stefan Priebe - Profihost AG
2011-08-26 2:16 ` Wu Fengguang
2011-08-26 2:16 ` Wu Fengguang
2011-08-26 2:54 ` Stefan Priebe - Profihost AG
2011-08-26 2:54 ` Stefan Priebe - Profihost AG
2011-08-26 3:03 ` Wu Fengguang
2011-08-26 3:03 ` Wu Fengguang
2011-08-26 3:13 ` Stefan Priebe
2011-08-26 3:13 ` Stefan Priebe
2011-08-26 3:26 ` Wu Fengguang
2011-08-26 3:26 ` Wu Fengguang
2011-08-26 3:30 ` Zhu Yanhai
2011-08-26 3:30 ` Zhu Yanhai
2011-08-26 6:18 ` Stefan Priebe - Profihost AG
2011-08-26 6:18 ` Stefan Priebe - Profihost AG
2011-08-31 7:11 ` Stefan Priebe - Profihost AG [this message]
2011-08-31 7:11 ` Stefan Priebe - Profihost AG
2011-09-01 4:14 ` Wu Fengguang
2011-09-01 4:14 ` Wu Fengguang
2011-09-01 5:41 ` Stefan Priebe - Profihost AG
2011-09-01 5:41 ` Stefan Priebe - Profihost AG
2011-09-01 12:57 ` Mel Gorman
2011-09-01 12:57 ` Mel Gorman
2011-08-24 9:32 ` Wu Fengguang
2011-08-24 9:32 ` Wu Fengguang
2011-08-24 9:32 ` Wu Fengguang
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