From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f196.google.com ([209.85.216.196]:37181 "EHLO mail-qt0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753843AbdHURig (ORCPT ); Mon, 21 Aug 2017 13:38:36 -0400 Received: by mail-qt0-f196.google.com with SMTP id g13so4457231qta.4 for ; Mon, 21 Aug 2017 10:38:35 -0700 (PDT) Date: Mon, 21 Aug 2017 13:38:34 -0400 From: Josef Bacik To: Liu Bo Cc: linux-btrfs@vger.kernel.org Subject: Re: [PATCH] Btrfs: do not async submit for nodatacsum inodes Message-ID: <20170821173833.GE23807@destiny> References: <20170818175402.27633-1-bo.li.liu@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20170818175402.27633-1-bo.li.liu@oracle.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Fri, Aug 18, 2017 at 11:54:02AM -0600, Liu Bo wrote: > While we submit direct writes, if the inode is flagged with nodatasum, > there's no benefit to submit asynchronously, because > > a) we don't have to calculate checksum across processors, > > b) and direct IO has started a plug, but async submit makes us queue > IO on each device's scheduled IO list instead of DIO's plug list, so > that IOs get much less merges in general. > > Lets use sync submit for nodatasum inodes. > > Signed-off-by: Liu Bo Reviewed-by: Josef Bacik Thanks, Josef