From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [PATCH] nfs: fix congestion control From: Peter Zijlstra In-Reply-To: References: <20070116054743.15358.77287.sendpatchset@schroedinger.engr.sgi.com> <20070116135325.3441f62b.akpm@osdl.org> <1168985323.5975.53.camel@lappy> <1169070763.5975.70.camel@lappy> <1169070886.6523.8.camel@lade.trondhjem.org> <1169126868.6197.55.camel@twins> <1169135375.6105.15.camel@lade.trondhjem.org> <1169199234.6197.129.camel@twins> <1169212022.6197.148.camel@twins> Content-Type: text/plain Date: Fri, 19 Jan 2007 18:57:41 +0100 Message-Id: <1169229461.6197.154.camel@twins> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Trond Myklebust , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, pj@sgi.com List-ID: On Fri, 2007-01-19 at 09:20 -0800, Christoph Lameter wrote: > On Fri, 19 Jan 2007, Peter Zijlstra wrote: > > > + /* > > + * NFS congestion size, scale with available memory. > > + * > > Well this all depends on the memory available to the running process. > If the process is just allowed to allocate from a subset of memory > (cpusets) then this may need to be lower. > > > + * 64MB: 8192k > > + * 128MB: 11585k > > + * 256MB: 16384k > > + * 512MB: 23170k > > + * 1GB: 32768k > > + * 2GB: 46340k > > + * 4GB: 65536k > > + * 8GB: 92681k > > + * 16GB: 131072k > > Hmmm... lets say we have the worst case of an 8TB IA64 system with 1k > nodes of 8G each. Eeuh, right. Glad to have you around to remind how puny my boxens are :-) > On Ia64 the number of pages is 8TB/16KB pagesize = 512 > million pages. Thus nfs_congestion_size is 724064 pages which is > 11.1Gbytes? > > If we now restrict a cpuset to a single node then have a > nfs_congestion_size of 11.1G vs an available memory on a node of 8G. Right, perhaps cap this to a max of 256M. That would allow 128 2M RPC transfers, much more would not be needed I guess. Trond? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org