linux-kernel - Re: [PATCH v2 0/3]CFQ: add think time check for service tree and group

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <4E1C3D5E.1050601@fusionio.com>
Date:	Tue, 12 Jul 2011 14:26:06 +0200
From:	Jens Axboe <jaxboe@...ionio.com>
To:	Shaohua Li <shaohua.li@...el.com>
CC:	lkml <linux-kernel@...r.kernel.org>,
	Vivek Goyal <vgoyal@...hat.com>
Subject: Re: [PATCH v2 0/3]CFQ: add think time check for service tree and
 group

On 2011-07-12 03:37, Shaohua Li wrote:
> Hi,
>   Currently when the last queue of a service tree/group is empty, CFQ
> doesn't expire the queue. This is to allow requests from the tree/group
> come soon, so tree/group doesn't miss its share. But if the think time
> is big, the assumption isn't correct. idling the queue is just wasting
> bandwidth.
> 
> Originally I was hoping this can resolve Vivek's fsync issue, but it
> doesn't. The fsync issue is caused by queue idling. But since think time
> check only helps for think time above default queue idle time (8ms),
> think time check doesn't help for the fsync issue.
> 
> On the other hand, think time check is still helpful for queues with
> think time. I had test case in follow patches show throughput
> improvement without sacrifice tree/group shares.
> 
> v1->v2:
> 1. addressed some good comments from Vivek
> 2. add more test to make sure the patches don't change behavior of
> queues without think time.

I applied 1-3, thanks. 1 was hand applied, since it didn't apply
directly to for-3.1/core after I merged Justins patch to get rid of the
meta data request special treatment.

-- 
Jens Axboe

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/