From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Tue, 22 Sep 2015 00:51:20 +0100 Subject: ARM64 readahead: fault retry breaks mmap file read random detection In-Reply-To: <56007868.8050605@android.com> References: <1442868028-27055-1-git-send-email-salyzyn@android.com> <20150921210938.GC7356@arm.com> <56007868.8050605@android.com> Message-ID: <20150921235120.GI7356@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Sep 21, 2015 at 10:36:40PM +0100, Mark Salyzyn wrote: > On 09/21/2015 02:09 PM, Will Deacon wrote: > > On Mon, Sep 21, 2015 at 09:39:50PM +0100, Mark Salyzyn wrote: > >> Description from commit 45cac65b0fcd > >> ("readahead: fault retry breaks mmap file read random detection") > >> . . . > >> Yup, arm64 needs this too! Random read improves by 250%, sequential > >> read improves by 40%, and random write by 400% to an eMMC device with > >> dm crypto wrapped around it. > > Thanks for this. This must've gone in whilst we were developing the initial > > version of the arm64 port and has since gone unnoticed. > > > > I'll queue it on the arm64 fixes branch and send a pull request after > > some testing. > > > As noted, this fix may need to be propagated to all the arch-specific > code, I was not in a position to check this out on arm (32 bit) and the > benchmarking code I used did not immediately port to 32-bit. You lost me; which arch-specific code are you referring to? The original patch (in mainline) touches a whole bunch of architectures. Will From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933179AbbIUXv2 (ORCPT ); Mon, 21 Sep 2015 19:51:28 -0400 Received: from foss.arm.com ([217.140.101.70]:55657 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932553AbbIUXvY (ORCPT ); Mon, 21 Sep 2015 19:51:24 -0400 Date: Tue, 22 Sep 2015 00:51:20 +0100 From: Will Deacon To: Mark Salyzyn Cc: "linux-kernel@vger.kernel.org" , Riley Andrews , Shaohua Li , Shaohua Li , Rik van Riel , Wu Fengguang , Catalin Marinas , Vladimir Murzin , Dave P Martin , David Hildenbrand , James Morse , Mark Rutland , "linux-arm-kernel@lists.infradead.org" Subject: Re: ARM64 readahead: fault retry breaks mmap file read random detection Message-ID: <20150921235120.GI7356@arm.com> References: <1442868028-27055-1-git-send-email-salyzyn@android.com> <20150921210938.GC7356@arm.com> <56007868.8050605@android.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <56007868.8050605@android.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 21, 2015 at 10:36:40PM +0100, Mark Salyzyn wrote: > On 09/21/2015 02:09 PM, Will Deacon wrote: > > On Mon, Sep 21, 2015 at 09:39:50PM +0100, Mark Salyzyn wrote: > >> Description from commit 45cac65b0fcd > >> ("readahead: fault retry breaks mmap file read random detection") > >> . . . > >> Yup, arm64 needs this too! Random read improves by 250%, sequential > >> read improves by 40%, and random write by 400% to an eMMC device with > >> dm crypto wrapped around it. > > Thanks for this. This must've gone in whilst we were developing the initial > > version of the arm64 port and has since gone unnoticed. > > > > I'll queue it on the arm64 fixes branch and send a pull request after > > some testing. > > > As noted, this fix may need to be propagated to all the arch-specific > code, I was not in a position to check this out on arm (32 bit) and the > benchmarking code I used did not immediately port to 32-bit. You lost me; which arch-specific code are you referring to? The original patch (in mainline) touches a whole bunch of architectures. Will