Return-Path: Received: from mail-io0-f194.google.com ([209.85.223.194]:35421 "EHLO mail-io0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754636AbdDQPaI (ORCPT ); Mon, 17 Apr 2017 11:30:08 -0400 Received: by mail-io0-f194.google.com with SMTP id d203so25181612iof.2 for ; Mon, 17 Apr 2017 08:30:07 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20170417133604.GA22694@fieldses.org> References: <20170413174515.GA5140@fieldses.org> <59BDF7CA-78BB-42FC-8BC4-95101F5E1EC7@netapp.com> <20170417133604.GA22694@fieldses.org> From: Olga Kornievskaia Date: Mon, 17 Apr 2017 11:30:06 -0400 Message-ID: Subject: Re: [nfsv4] Inter server-side copy performance To: "J. Bruce Fields" Cc: "linux-nfs@vger.kernel.org" , "nfsv4@ietf.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, Apr 17, 2017 at 9:36 AM, J. Bruce Fields wrote: > On Fri, Apr 14, 2017 at 05:22:13PM -0400, Olga Kornievskaia wrote: >> On Fri, Apr 14, 2017 at 4:09 PM, Mora, Jorge wrote: >> > On 4/13/17, 11:45 AM, "J. Bruce Fields" wrote: >> >> Are you timing just the copy_file_range() call, or do you include a >> >> following sync? >> > >> > I am timing right before calling copy_file_range() up to doing an fsync() and close() of the destination file. >> > For the traditional copy is the same, I am timing right before the first read on the source file up to the >> > fsync() and close() of the destination file. >> >> Why should do we need a sync after copy_file_range(). kernel >> copy_file_range() will send the commits for any unstable copies it >> received. > > Why does it do that? As far as I can tell it's not required by > documentation for copy_file_range() or COPY. COPY has a write verifier > and a stable_how argument in the reply. Skipping the commits would > allow better performance in case a copy requires multiple COPY calls. > > But, in any case, if copy_file_range() already committed then it > probably doesn't make a significant difference to the timing whether you > include a following sync and/or close. Hm. It does make sense. Anna wrote the original code which included the COMMIT after copy which I haven't thought about. Anna, any comments?