From: Steve Rago <sar-a+KepyhlMvJWk0Htik3J/w@public.gmane.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>,
linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org,
Trond.Myklebust@netapp.com, Wu Fengguang <fengguang.wu@intel.com>,
"jens.axboe" <jens.axboe@oracle.com>
Subject: Re: [PATCH] improve the performance of large sequential write NFS workloads
Date: Fri, 18 Dec 2009 16:20:11 -0500 [thread overview]
Message-ID: <1261171211.1947.135.camel@serenity> (raw)
In-Reply-To: <20091218194129.GB6153@elte.hu>
On Fri, 2009-12-18 at 20:41 +0100, Ingo Molnar wrote:
> * Steve Rago <sar-a+KepyhlMvJWk0Htik3J/w@public.gmane.org> wrote:
>
> > > Also, I don't think this needs to have a sysctl, it should just work.
> >
> > The sysctl is a *good thing* in that it allows the eager writeback behavior
> > to be tuned and shut off if need be. I can only test the changes on a
> > finite set of systems, so better safe than sorry.
>
> This issue has been settled many years ago and that's not what we do in the
> Linux kernel. We prefer patches to core code where we are reasonably sure they
> result in good behavior - and then we fix bugs in the new behavior, if any.
>
> (Otherwise odd sysctls would mushroom quickly and the system would become
> untestable in practice.)
>
> Ingo
I don't disagree, but "that's not what we do" hardly provides insight
into making the judgment call. In this case, the variety of
combinations of NFS server speed, NFS client speed, transmission link
speed, client memory size, and server memory size argues for a tunable
parameter, because one value probably won't work well in all
combinations. Making it change dynamically based on these parameters is
more complicated than these circumstances call for, IMHO.
Steve
next prev parent reply other threads:[~2009-12-18 21:20 UTC|newest]
Thread overview: 96+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-17 2:03 [PATCH] improve the performance of large sequential write NFS workloads Steve Rago
2009-12-17 8:17 ` Peter Zijlstra
2009-12-18 19:33 ` Steve Rago
2009-12-18 19:41 ` Ingo Molnar
2009-12-18 21:20 ` Steve Rago [this message]
2009-12-18 22:07 ` Ingo Molnar
2009-12-18 22:46 ` Steve Rago
2009-12-19 8:08 ` Arjan van de Ven
2009-12-19 13:37 ` Steve Rago
2009-12-18 19:44 ` Peter Zijlstra
2009-12-19 12:20 ` Wu Fengguang
2009-12-19 14:25 ` Steve Rago
2009-12-22 1:59 ` Wu Fengguang
2009-12-22 12:35 ` Jan Kara
[not found] ` <20091222123538.GB604-jyMamyUUXNJG4ohzP4jBZS1Fcj925eT/@public.gmane.org>
2009-12-23 8:43 ` Christoph Hellwig
2009-12-23 13:32 ` Jan Kara
[not found] ` <20091223133244.GB3159-+0h/O2h83AeN3ZZ/Hiejyg@public.gmane.org>
2009-12-24 5:25 ` Wu Fengguang
2009-12-24 1:26 ` Wu Fengguang
2009-12-22 13:01 ` Martin Knoblauch
[not found] ` <787373.9318.qm-rpBZDh8Qtqs5A34FEqDeB/u2YVrzzGjVVpNB7YpNyf8@public.gmane.org>
2009-12-24 1:46 ` Wu Fengguang
2009-12-22 16:41 ` Steve Rago
2009-12-24 1:21 ` Wu Fengguang
2009-12-24 14:49 ` Steve Rago
2009-12-25 7:37 ` Wu Fengguang
2009-12-23 14:21 ` Trond Myklebust
2009-12-23 18:05 ` Jan Kara
[not found] ` <20091223180551.GD3159-+0h/O2h83AeN3ZZ/Hiejyg@public.gmane.org>
2009-12-23 19:12 ` Trond Myklebust
2009-12-24 2:52 ` Wu Fengguang
2009-12-24 12:04 ` Trond Myklebust
2009-12-25 5:56 ` Wu Fengguang
2009-12-30 16:22 ` Trond Myklebust
2009-12-31 5:04 ` Wu Fengguang
2009-12-31 19:13 ` Trond Myklebust
2010-01-06 3:03 ` Wu Fengguang
2010-01-06 16:56 ` Trond Myklebust
2010-01-06 18:26 ` Trond Myklebust
2010-01-06 18:37 ` Peter Zijlstra
2010-01-06 18:52 ` Trond Myklebust
2010-01-06 19:07 ` Peter Zijlstra
2010-01-06 19:21 ` Trond Myklebust
2010-01-06 19:53 ` Trond Myklebust
2010-01-06 20:09 ` Jan Kara
2010-01-06 20:51 ` [PATCH 0/6] " Trond Myklebust
[not found] ` <20100106205110.22547.85345.stgit-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2010-01-06 20:51 ` [PATCH 2/6] VM/NFS: The VM must tell the filesystem when to free reclaimable pages Trond Myklebust
2010-01-07 2:29 ` Wu Fengguang
2010-01-07 4:49 ` Trond Myklebust
2010-01-07 5:03 ` Wu Fengguang
2010-01-07 5:30 ` Trond Myklebust
2010-01-07 14:37 ` Wu Fengguang
2010-01-07 14:41 ` [PATCH 0/5] Re: [PATCH] improve the performance of large sequential write NFS workloads Trond Myklebust
[not found] ` <20100107144137.17158.53673.stgit-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2010-01-07 14:41 ` [PATCH 2/5] VM: Split out the accounting of unstable writes from BDI_RECLAIMABLE Trond Myklebust
2010-01-07 14:41 ` [PATCH 4/5] VM/NFS: The VM must tell the filesystem when to free reclaimable pages Trond Myklebust
2010-01-07 14:41 ` [PATCH 5/5] NFS: Run COMMIT as an asynchronous RPC call when wbc->for_background is set Trond Myklebust
2010-01-07 14:41 ` [PATCH 1/5] VFS: Ensure that writeback_single_inode() commits unstable writes Trond Myklebust
2010-01-07 14:41 ` [PATCH 3/5] VM: Don't call bdi_stat(BDI_UNSTABLE) on non-nfs backing-devices Trond Myklebust
2010-01-06 20:51 ` [PATCH 3/6] VM: Split out the accounting of unstable writes from BDI_RECLAIMABLE Trond Myklebust
[not found] ` <20100106205110.22547.93554.stgit-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2010-01-07 1:48 ` Wu Fengguang
2010-01-06 20:51 ` [PATCH 5/6] VM: Use per-bdi unstable accounting to improve use of wbc->force_commit Trond Myklebust
[not found] ` <20100106205110.22547.32584.stgit-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2010-01-07 2:34 ` Wu Fengguang
2010-01-06 20:51 ` [PATCH 6/6] NFS: Run COMMIT as an asynchronous RPC call when wbc->for_background is set Trond Myklebust
[not found] ` <20100106205110.22547.31434.stgit-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2010-01-07 2:32 ` Wu Fengguang
2010-01-06 20:51 ` [PATCH 4/6] VM: Don't call bdi_stat(BDI_UNSTABLE) on non-nfs backing-devices Trond Myklebust
2010-01-07 1:56 ` Wu Fengguang
2010-01-06 20:51 ` [PATCH 1/6] VFS: Ensure that writeback_single_inode() commits unstable writes Trond Myklebust
[not found] ` <20100106205110.22547.17971.stgit-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2010-01-06 21:38 ` Jan Kara
[not found] ` <20100106213843.GD22781-+0h/O2h83AeN3ZZ/Hiejyg@public.gmane.org>
2010-01-06 21:48 ` Trond Myklebust
2010-01-07 2:18 ` Wu Fengguang
[not found] ` <1262839082.2185.15.camel@localhost>
2010-01-07 4:48 ` Wu Fengguang
2010-01-07 4:53 ` [PATCH 0/5] Re: [PATCH] improve the performance of large sequential write NFS workloads Trond Myklebust
[not found] ` <20100107045330.5986.55090.stgit-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2010-01-07 4:53 ` [PATCH 3/5] VM: Don't call bdi_stat(BDI_UNSTABLE) on non-nfs backing-devices Trond Myklebust
2010-01-07 4:53 ` [PATCH 5/5] NFS: Run COMMIT as an asynchronous RPC call when wbc->for_background is set Trond Myklebust
2010-01-07 4:53 ` [PATCH 2/5] VM: Split out the accounting of unstable writes from BDI_RECLAIMABLE Trond Myklebust
2010-01-07 4:53 ` [PATCH 1/5] VFS: Ensure that writeback_single_inode() commits unstable writes Trond Myklebust
2010-01-07 4:53 ` [PATCH 4/5] VM/NFS: The VM must tell the filesystem when to free reclaimable pages Trond Myklebust
2010-01-07 14:56 ` [PATCH 1/6] VFS: Ensure that writeback_single_inode() commits unstable writes Wu Fengguang
2010-01-07 15:10 ` Trond Myklebust
2010-01-08 1:17 ` Wu Fengguang
2010-01-08 1:37 ` Trond Myklebust
2010-01-08 1:53 ` Wu Fengguang
2010-01-08 9:25 ` Christoph Hellwig
2010-01-08 13:46 ` Trond Myklebust
2010-01-08 13:54 ` Christoph Hellwig
2010-01-08 14:15 ` Trond Myklebust
2010-01-06 21:44 ` [PATCH 0/6] Re: [PATCH] improve the performance of large sequential write NFS workloads Jan Kara
2010-01-06 22:03 ` Trond Myklebust
2010-01-07 8:16 ` Peter Zijlstra
2009-12-22 12:25 ` Jan Kara
[not found] ` <20091222122557.GA604-jyMamyUUXNJG4ohzP4jBZS1Fcj925eT/@public.gmane.org>
2009-12-22 12:38 ` Peter Zijlstra
2009-12-22 12:55 ` Jan Kara
2009-12-22 16:20 ` Steve Rago
2009-12-23 18:39 ` Jan Kara
[not found] ` <20091223183912.GE3159-+0h/O2h83AeN3ZZ/Hiejyg@public.gmane.org>
2009-12-23 20:16 ` Steve Rago
2009-12-23 21:49 ` Trond Myklebust
2009-12-23 23:13 ` Steve Rago
2009-12-23 23:44 ` Trond Myklebust
2009-12-24 4:30 ` Steve Rago
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=1261171211.1947.135.camel@serenity \
--to=sar-a+kepyhlmvjwk0htik3j/w@public.gmane.org \
--cc=Trond.Myklebust@netapp.com \
--cc=fengguang.wu@intel.com \
--cc=jens.axboe@oracle.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-nfs@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=peterz@infradead.org \
/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