Return-Path: Received: from mx141.netapp.com ([216.240.21.12]:19294 "EHLO mx141.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751906AbbCYRPJ (ORCPT ); Wed, 25 Mar 2015 13:15:09 -0400 Message-ID: <5512ED19.4060902@Netapp.com> Date: Wed, 25 Mar 2015 13:15:05 -0400 From: Anna Schumaker MIME-Version: 1.0 To: Christoph Hellwig CC: "J. Bruce Fields" , Marc Eshel , "linux-nfs@vger.kernel.org" , , Subject: Re: [PATCH v3 3/3] NFSD: Add support for encoding multiple segments References: <20150318205554.GA10716@fieldses.org> <5509E824.6070006@Netapp.com> <20150318211144.GB10716@fieldses.org> <20150319153627.GA20852@fieldses.org> <20150320151718.GD2036@fieldses.org> <20150320162303.GA18786@infradead.org> <20150320182621.GH2036@fieldses.org> <20150324174916.GA28906@infradead.org> In-Reply-To: <20150324174916.GA28906@infradead.org> Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: On 03/24/2015 01:49 PM, Christoph Hellwig wrote: > On Tue, Mar 24, 2015 at 08:43:31AM -0400, Anna Schumaker wrote: >>> I don't know, and don't have profiles. I'll either try to reproduce or >>> wait till Anna's back from vacation. >> >> I'm using whatever functions NFSD already uses for reading files, >> which I expect go through the VFS. Is there a flag that controls >> cache behavior? > > There's the O_DIRECT flag, but that's not what I mean. If you just > wrote to it it's a cached read, if you did unmount the filesystem after > writing, or did an echo to /proc/sys/vm/drop_caches you get uncached > read behavior. Oh, I'm doing uncached reads for my tests. I'm collecting updated numbers now! Anna >