From: Jens Axboe <axboe@kernel.dk>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: Shaohua Li <shaohua.li@intel.com>, Tao Ma <tm@tao.ma>,
linux-kernel@vger.kernel.org
Subject: Re: CFQ: async queue blocks the whole system
Date: Fri, 10 Jun 2011 11:20:43 +0200 [thread overview]
Message-ID: <4DF1E1EB.8010808@kernel.dk> (raw)
In-Reply-To: <20110610091747.GC4183@redhat.com>
On 2011-06-10 11:17, Vivek Goyal wrote:
> On Fri, Jun 10, 2011 at 09:19:12AM +0800, Shaohua Li wrote:
>
> [..]
>>> If there is no major advantage of draining sync requests before async
>>> is dispatched, I think this should be an easy fix.
>> I thought this is to avoid sync latency if we switch from an async
>> queue to sync queue later.
>
> Is it about the sync request latency which has already been dispatched? I
> really wish that driver and disk should do some prioritazation for reads
> here and CFQ does not have to jump through hoops like drain sync requests
> before async requests are dispatched.
That would never work. Are you suggesting putting that logic in all
drivers? Or relying on hardware to get the fairness right? Not going to
happen.
--
Jens Axboe
next prev parent reply other threads:[~2011-06-10 9:20 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-09 10:49 CFQ: async queue blocks the whole system Tao Ma
2011-06-09 14:14 ` Vivek Goyal
2011-06-09 14:34 ` Jens Axboe
2011-06-09 14:47 ` Tao Ma
2011-06-09 15:37 ` Vivek Goyal
2011-06-09 15:44 ` Tao Ma
2011-06-09 18:27 ` Vivek Goyal
2011-06-10 5:48 ` Tao Ma
2011-06-10 9:14 ` Vivek Goyal
2011-06-10 10:00 ` Tao Ma
2011-06-10 15:44 ` Vivek Goyal
2011-06-11 7:24 ` Tao Ma
2011-06-13 10:08 ` Tao Ma
2011-06-13 21:41 ` Vivek Goyal
2011-06-14 7:03 ` Tao Ma
2011-06-14 13:30 ` Vivek Goyal
2011-06-14 15:42 ` Tao Ma
2011-06-14 21:14 ` Vivek Goyal
2011-06-17 3:04 ` Tao Ma
2011-06-17 12:50 ` Vivek Goyal
2011-06-17 14:34 ` Tao Ma
2011-06-10 1:19 ` Shaohua Li
2011-06-10 1:34 ` Shaohua Li
2011-06-10 2:06 ` Tao Ma
2011-06-10 2:35 ` Shaohua Li
2011-06-10 3:02 ` Tao Ma
2011-06-10 9:20 ` Vivek Goyal
2011-06-10 9:21 ` Jens Axboe
2011-06-13 1:03 ` Shaohua Li
2011-06-10 9:17 ` Vivek Goyal
2011-06-10 9:20 ` Jens Axboe [this message]
2011-06-10 9:29 ` Vivek Goyal
2011-06-10 9:31 ` Jens Axboe
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4DF1E1EB.8010808@kernel.dk \
--to=axboe@kernel.dk \
--cc=linux-kernel@vger.kernel.org \
--cc=shaohua.li@intel.com \
--cc=tm@tao.ma \
--cc=vgoyal@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox