linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Jens Axboe <axboe@suse.de>
To: Chris Mason <mason@suse.com>
Cc: Andrea Arcangeli <andrea@suse.de>,
	Marcelo Tosatti <marcelo@conectiva.com.br>,
	lkml <linux-kernel@vger.kernel.org>,
	"Stephen C. Tweedie" <sct@redhat.com>,
	Alan Cox <alan@lxorguk.ukuu.org.uk>,
	Jeff Garzik <jgarzik@pobox.com>, Andrew Morton <akpm@digeo.com>,
	Alexander Viro <viro@math.psu.edu>
Subject: Re: RFC on io-stalls patch
Date: Tue, 15 Jul 2003 07:43:04 +0200	[thread overview]
Message-ID: <20030715054304.GC833@suse.de> (raw)
In-Reply-To: <1058229360.13317.364.camel@tiny.suse.com>

On Mon, Jul 14 2003, Chris Mason wrote:
> On Mon, 2003-07-14 at 18:45, Andrea Arcangeli wrote:
> > On Mon, Jul 14, 2003 at 04:34:41PM -0400, Chris Mason wrote:
> > > patch.  It's a good starting point for the question "can we do better
> > > for reads?" (clearly the answer is yes).
> > 
> > Jens's patch will block every writers until the parallel sync readers go
> > away.  if we add a 5 seconds delay for every write, sure readers will
> > run faster too in contest, and in turn it's not obvious to me it's
> > necessairly a good starting point.  
> 
> For real server workloads I agree the patch isn't a good idea.  But
> Jens' workload had a small number of kernel compilers (was it one proc
> or make -j4 or so?), so clearly the writers could still make progress. 
> This doesn't mean I want the patch but it does mean the numbers are
> worth thinking about ;-)
> 
> If we go back to Jens' numbers:
> 
> ctar_load:
> Kernel            [runs]        Time    CPU%    Loads   LCPU%   Ratio
> 2.4.22-pre5            3        235     114.0   25.0    22.1    1.75
> 2.4.22-pre5-axboe      3        194     138.1   19.7    20.6    1.46
>                                                ^^^^^^
> The loads column is the number of times ctar_load managed to run during
> the kernel compile, and the patched kernel loses each time.  This must
> partially be caused by the lower run time overall, but it is still
> important data.  It would be better if contest gave us some kind of
> throughput numbers (avg load time or something).

Well, look at the ratio given the run times listed. You'll see that they
are extremely close (0.1064 for 2.4.22-pre5 vs 0.1015 for
2.4.22-pre5-axboe).

It just shows that we are not hitting the possible bad problems in these
work loads.

-- 
Jens Axboe


  parent reply	other threads:[~2003-07-15  5:28 UTC|newest]

Thread overview: 68+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-07-08 20:06 RFC on io-stalls patch Marcelo Tosatti
2003-07-10 13:57 ` Jens Axboe
2003-07-11 14:13   ` Chris Mason
2003-07-12  0:20     ` Nick Piggin
2003-07-12 18:37       ` Chris Mason
2003-07-12  7:37     ` Jens Axboe
2003-07-12  7:48       ` Jens Axboe
2003-07-12 18:32       ` Chris Mason
2003-07-13  0:33         ` Andrea Arcangeli
2003-07-13  9:01         ` Jens Axboe
2003-07-13 16:20           ` Chris Mason
2003-07-13 16:45             ` Jeff Garzik
2003-07-13 19:33               ` Andrea Arcangeli
2003-07-13 17:47             ` Jens Axboe
2003-07-13 19:35               ` Andrea Arcangeli
2003-07-14  0:36                 ` Chris Mason
2003-07-13 19:19           ` Andrea Arcangeli
2003-07-14  5:49             ` Jens Axboe
2003-07-14 12:23               ` Marcelo Tosatti
2003-07-14 13:12                 ` Jens Axboe
2003-07-14 19:51                   ` Jens Axboe
2003-07-14 20:09                     ` Chris Mason
2003-07-14 20:19                       ` Andrea Arcangeli
2003-07-14 21:24                         ` Chris Mason
2003-07-15  5:46                       ` Jens Axboe
2003-07-14 20:09                     ` Marcelo Tosatti
2003-07-14 20:24                       ` Andrea Arcangeli
2003-07-14 20:34                         ` Chris Mason
2003-07-15  5:35                           ` Jens Axboe
     [not found]                           ` <20030714224528.GU16313@dualathlon.random>
2003-07-15  5:40                             ` Jens Axboe
     [not found]                             ` <1058229360.13317.364.camel@tiny.suse.com>
2003-07-15  5:43                               ` Jens Axboe [this message]
     [not found]                               ` <20030714175238.3eaddd9a.akpm@osdl.org>
     [not found]                                 ` <20030715020706.GC16313@dualathlon.random>
2003-07-15  5:45                                   ` Jens Axboe
2003-07-15  6:01                                     ` Andrea Arcangeli
2003-07-15  6:08                                       ` Jens Axboe
2003-07-15  7:03                                         ` Andrea Arcangeli
2003-07-15  8:28                                           ` Jens Axboe
2003-07-15  9:12                                             ` Chris Mason
2003-07-15  9:17                                               ` Jens Axboe
2003-07-15  9:18                                                 ` Jens Axboe
2003-07-15  9:30                                                   ` Chris Mason
2003-07-15 10:03                                                   ` Andrea Arcangeli
2003-07-15 10:11                                                     ` Jens Axboe
2003-07-15 14:18                                                 ` Chris Mason
2003-07-15 14:29                                                   ` Jens Axboe
2003-07-16 17:06                                                   ` Chris Mason
2003-07-15  9:22                                               ` Chris Mason
2003-07-15  9:59                                               ` Andrea Arcangeli
2003-07-15  9:48                                             ` Andrea Arcangeli
2003-07-14 20:16                     ` Andrea Arcangeli
2003-07-14 20:17                       ` Marcelo Tosatti
2003-07-14 20:27                         ` Andrea Arcangeli
2003-07-15  5:26                       ` Jens Axboe
2003-07-15  5:48                         ` Andrea Arcangeli
2003-07-15  6:01                           ` Jens Axboe
2003-07-15  6:33                             ` Andrea Arcangeli
2003-07-15 11:22                         ` Alan Cox
2003-07-15 11:27                           ` Jens Axboe
2003-07-16 12:43                             ` Andrea Arcangeli
2003-07-16 12:46                               ` Jens Axboe
2003-07-16 12:59                                 ` Andrea Arcangeli
2003-07-16 13:04                                   ` Jens Axboe
2003-07-16 13:11                                     ` Andrea Arcangeli
2003-07-16 13:21                                       ` Jens Axboe
2003-07-16 13:44                                         ` Andrea Arcangeli
2003-07-16 14:00                                           ` Jens Axboe
2003-07-16 14:24                                             ` Andrea Arcangeli
2003-07-16 16:49                                     ` Andrew Morton
2003-07-15 18:47 Shane Shrybman

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=20030715054304.GC833@suse.de \
    --to=axboe@suse.de \
    --cc=akpm@digeo.com \
    --cc=alan@lxorguk.ukuu.org.uk \
    --cc=andrea@suse.de \
    --cc=jgarzik@pobox.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=marcelo@conectiva.com.br \
    --cc=mason@suse.com \
    --cc=sct@redhat.com \
    --cc=viro@math.psu.edu \
    /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;
as well as URLs for NNTP newsgroup(s).