From: jmerkey <jmerkey@utah-nac.org>
To: Jens Axboe <axboe@suse.de>
Cc: Holger Kiehl <Holger.Kiehl@dwd.de>,
Vojtech Pavlik <vojtech@suse.cz>,
linux-raid <linux-raid@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: Where is the performance bottleneck?
Date: Wed, 31 Aug 2005 09:59:39 -0600 [thread overview]
Message-ID: <4315D3EB.4000601@utah-nac.org> (raw)
In-Reply-To: <20050831171124.GH4018@suse.de>
512 is not enough. It has to be larger. I just tried 512 and it still
limits the data rates.
Jeff
Jens Axboe wrote:
>On Wed, Aug 31 2005, jmerkey wrote:
>
>
>>I have seen an 80GB/sec limitation in the kernel unless this value is
>>changed in the SCSI I/O layer
>>for 3Ware and other controllers during testing of 2.6.X series kernels.
>>
>>Change these values in include/linux/blkdev.h and performance goes from
>>80MB/S to over 670MB/S on the 3Ware controller.
>>
>>
>>//#define BLKDEV_MIN_RQ 4
>>//#define BLKDEV_MAX_RQ 128 /* Default maximum */
>>#define BLKDEV_MIN_RQ 4096
>>#define BLKDEV_MAX_RQ 8192 /* Default maximum */
>>
>>
>
>That's insane, you just wasted 1MiB of preallocated requests on each
>queue in the system!
>
>Please just do
>
># echo 512 > /sys/block/dev/queue/nr_requests
>
>after boot for each device you want to increase the queue size too. 512
>should be enough with the 3ware.
>
>
>
next prev parent reply other threads:[~2005-08-31 15:59 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-08-29 18:20 Where is the performance bottleneck? Holger Kiehl
2005-08-29 19:54 ` Mark Hahn
2005-08-30 19:08 ` Holger Kiehl
2005-08-30 23:05 ` Guy
2005-09-28 20:04 ` Bill Davidsen
2005-09-30 4:52 ` Guy
2005-09-30 5:19 ` dean gaudet
2005-10-06 21:15 ` Bill Davidsen
2005-08-29 20:10 ` Al Boldi
2005-08-30 19:18 ` Holger Kiehl
2005-08-31 10:30 ` Al Boldi
2005-08-29 20:25 ` Vojtech Pavlik
2005-08-30 20:06 ` Holger Kiehl
2005-08-31 7:11 ` Vojtech Pavlik
2005-08-31 7:26 ` Jens Axboe
2005-08-31 11:54 ` Holger Kiehl
2005-08-31 12:07 ` Jens Axboe
2005-08-31 13:55 ` Holger Kiehl
2005-08-31 14:24 ` Dr. David Alan Gilbert
2005-08-31 20:56 ` Holger Kiehl
2005-08-31 21:16 ` Dr. David Alan Gilbert
2005-08-31 16:20 ` Jens Axboe
2005-08-31 15:16 ` jmerkey
2005-08-31 16:58 ` Tom Callahan
2005-08-31 16:58 ` Tom Callahan
2005-08-31 15:47 ` jmerkey
2005-08-31 17:11 ` Jens Axboe
2005-08-31 15:59 ` jmerkey [this message]
2005-08-31 17:32 ` Jens Axboe
2005-08-31 16:51 ` Holger Kiehl
2005-08-31 17:35 ` Jens Axboe
2005-08-31 19:00 ` Holger Kiehl
2005-08-31 18:06 ` Michael Tokarev
2005-08-31 18:52 ` Ming Zhang
2005-08-31 18:57 ` Ming Zhang
2005-08-31 12:24 ` Nick Piggin
2005-08-31 16:25 ` Holger Kiehl
2005-08-31 17:25 ` Nick Piggin
2005-08-31 21:57 ` Holger Kiehl
2005-09-01 9:12 ` Holger Kiehl
2005-09-02 14:28 ` Al Boldi
2005-08-31 13:38 ` Holger Kiehl
2005-08-29 23:09 ` Peter Chubb
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=4315D3EB.4000601@utah-nac.org \
--to=jmerkey@utah-nac.org \
--cc=Holger.Kiehl@dwd.de \
--cc=axboe@suse.de \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-raid@vger.kernel.org \
--cc=vojtech@suse.cz \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.