From: Martin Knoblauch Subject: Re: [PATCH] improve the performance of large sequential write NFS workloads Date: Tue, 22 Dec 2009 05:01:46 -0800 (PST) Message-ID: <787373.9318.qm@web113309.mail.gq1.yahoo.com> References: <1261015420.1947.54.camel@serenity> <1261037877.27920.36.camel@laptop> <20091219122033.GA11360@localhost> <1261232747.1947.194.camel@serenity> <20091222015907.GA6223@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Peter Zijlstra , "linux-nfs@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "Trond.Myklebust@netapp.com" , "jens.axboe" To: Wu Fengguang , Steve Rago Return-path: Received: from web113309.mail.gq1.yahoo.com ([98.136.167.9]:48061 "HELO web113309.mail.gq1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751153AbZLVNI2 (ORCPT ); Tue, 22 Dec 2009 08:08:28 -0500 In-Reply-To: <20091222015907.GA6223@localhost> Sender: linux-nfs-owner@vger.kernel.org List-ID: ----- Original Message ---- > From: Wu Fengguang > To: Steve Rago > Cc: Peter Zijlstra ; "linux-nfs@vger.kernel.org" ; "linux-kernel@vger.kernel.org" ; "Trond.Myklebust@netapp.com" ; jens.axboe > Sent: Tue, December 22, 2009 2:59:07 AM > Subject: Re: [PATCH] improve the performance of large sequential write NFS workloads > [big snip] > > In general it's reasonable to keep NFS per-file nr_dirty low, however > questionable to do per-file nr_writeback throttling. This does not > work well with the global limits - eg. when there are many dirty > files, the summed-up nr_writeback will still grow out of control. > And it's more likely to impact user visible responsiveness than > a global limit. But my opinion can be biased -- me have a patch to > do global NFS nr_writeback limit ;) > is that "NFS: introduce writeback wait queue", which you sent me a while ago and I did not test until now :-( ? Cheers Martin