linux-kernel - Re: [PATCH]cfq-iosched: don't stop async queue with async requests pending

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

Message-ID: <20100113082322.GA24345@sli10-desk.sh.intel.com>
Date:	Wed, 13 Jan 2010 16:23:22 +0800
From:	Shaohua Li <shaohua.li@...el.com>
To:	Corrado Zoccolo <czoccolo@...il.com>
Cc:	"jens.axboe@...cle.com" <jens.axboe@...cle.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"jmoyer@...hat.com" <jmoyer@...hat.com>,
	"vgoyal@...hat.com" <vgoyal@...hat.com>,
	"guijianfeng@...fujitsu.com" <guijianfeng@...fujitsu.com>,
	"yanmin_zhang@...ux.intel.com" <yanmin_zhang@...ux.intel.com>
Subject: Re: [PATCH]cfq-iosched: don't stop async queue with async requests
 pending

On Wed, Jan 13, 2010 at 04:18:47PM +0800, Corrado Zoccolo wrote:
> On Wed, Jan 13, 2010 at 8:44 AM, Shaohua Li <shaohua.li@...el.com> wrote:
> > My SSD speed of direct write is about 80m/s, while I test page writeback,
> > the speed can only go to 68m/s. Below patch fixes this.
> > It appears we missused cfq_should_idle in cfq_may_dispatch. cfq_should_idle
> > means a queue should idle because it's seekless sync queue or it's the last queue,
> > which is to maintain service tree time slice. So it doesn't mean the
> > last queue is always a sync queue. If the last queue is asyn queue,
> > we definitely shouldn't stop dispatch requests because of pending async
> > requests.
> 
> An other option is that cfq_should_idle returns false for async
> queues, since cfq will never idle on them.
I'm considering this option too, but it appears we need make async queue
idle to maintain domain time slice.

Thanks,
Shaohua
--
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/