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From: Jens Axboe <axboe@suse.de>
To: Giuliano Pochini <pochini@denise.shiny.it>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: Time sliced CFQ io scheduler
Date: Thu, 2 Dec 2004 15:41:34 +0100	[thread overview]
Message-ID: <20041202144129.GI10458@suse.de> (raw)
In-Reply-To: <Pine.LNX.4.58.0412021517070.3471@denise.shiny.it>

On Thu, Dec 02 2004, Giuliano Pochini wrote:
> 
> 
> On Thu, 2 Dec 2004, Jens Axboe wrote:
> 
> > Case 4: write_files, random, bs=4k
> 
> Just a thought... in this test the results don't look right. Why
> aggregate bandwidth with 8 clients is higher than with 4 and 2 clients ?
> In the cfq test with 8 clients aggregate bw is also higher than with
> a single client.

I don't know what happens with the 4 client case, but it's not that
unlikely that aggregate bandwidth will be higher for more threads doing
random writes, as request coalesching will help minimize seeks.

But I did think it was strange with the 4 client case dip was strange,
it was reproducable though (as are all the results, they have very
little variance).

-- 
Jens Axboe


  reply	other threads:[~2004-12-02 14:42 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-12-02 13:04 Time sliced CFQ io scheduler Jens Axboe
2004-12-02 13:48 ` Jens Axboe
2004-12-02 19:48   ` Andrew Morton
2004-12-02 19:52     ` Jens Axboe
2004-12-02 20:19       ` Andrew Morton
2004-12-02 20:19         ` Jens Axboe
2004-12-02 20:34           ` Andrew Morton
2004-12-02 20:37             ` Jens Axboe
2004-12-07 23:11               ` Nick Piggin
2004-12-02 22:18         ` Prakash K. Cheemplavam
2004-12-03  7:01           ` Jens Axboe
2004-12-03  9:12             ` Prakash K. Cheemplavam
2004-12-03  9:18               ` Jens Axboe
2004-12-03  9:35                 ` Prakash K. Cheemplavam
2004-12-03  9:43                   ` Jens Axboe
2004-12-03  9:26               ` Andrew Morton
2004-12-03  9:34                 ` Prakash K. Cheemplavam
2004-12-03  9:39                 ` Jens Axboe
2004-12-03  9:54                   ` Prakash K. Cheemplavam
     [not found]                   ` <41B03722.5090001@gmx.de>
2004-12-03 10:31                     ` Jens Axboe
2004-12-03 10:38                       ` Jens Axboe
2004-12-03 10:45                         ` Prakash K. Cheemplavam
2004-12-03 10:48                           ` Jens Axboe
2004-12-03 11:27                             ` Prakash K. Cheemplavam
2004-12-03 11:29                               ` Jens Axboe
2004-12-03 11:52                                 ` Prakash K. Cheemplavam
2004-12-08  0:37       ` Andrea Arcangeli
2004-12-08  0:54         ` Nick Piggin
2004-12-08  1:37           ` Andrea Arcangeli
2004-12-08  1:47             ` Nick Piggin
2004-12-08  2:09               ` Andrea Arcangeli
2004-12-08  2:11                 ` Andrew Morton
2004-12-08  2:22                   ` Andrea Arcangeli
2004-12-08  6:52               ` Jens Axboe
2004-12-08  2:00             ` Andrew Morton
2004-12-08  2:08               ` Andrew Morton
2004-12-08  6:55                 ` Jens Axboe
2004-12-08  2:20               ` Andrea Arcangeli
2004-12-08  2:25                 ` Andrew Morton
2004-12-08  2:33                   ` Andrea Arcangeli
2004-12-08  2:33                   ` Nick Piggin
2004-12-08  2:51                     ` Andrea Arcangeli
2004-12-08  3:02                       ` Nick Piggin
2004-12-08  6:58                     ` Jens Axboe
2004-12-08  7:14                       ` Nick Piggin
2004-12-08  7:20                         ` Jens Axboe
2004-12-08  7:29                           ` Nick Piggin
2004-12-08  7:32                             ` Jens Axboe
2004-12-08  7:30                           ` Andrew Morton
2004-12-08  7:36                             ` Jens Axboe
2004-12-08 13:48                         ` Jens Axboe
2004-12-08  6:55               ` Jens Axboe
2004-12-08  7:08                 ` Nick Piggin
2004-12-08  7:11                   ` Jens Axboe
2004-12-08  7:19                     ` Nick Piggin
2004-12-08  7:26                       ` Jens Axboe
2004-12-08  9:35                         ` Jens Axboe
2004-12-08 10:08                           ` Jens Axboe
2004-12-08 12:47                           ` Jens Axboe
2004-12-08 10:52                 ` Helge Hafting
2004-12-08 10:49                   ` Jens Axboe
2004-12-08  6:49           ` Jens Axboe
2004-12-02 14:28 ` Giuliano Pochini
2004-12-02 14:41   ` Jens Axboe [this message]
2004-12-04 13:05     ` Giuliano Pochini
  -- strict thread matches above, loose matches on Subject: below --
2004-12-03 20:52 Chuck Ebbert

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