From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from moutng.kundenserver.de ([212.227.126.183]) by bombadil.infradead.org with esmtp (Exim 4.68 #1 (Red Hat Linux)) id 1JjxXR-0001dh-76 for linux-mtd@lists.infradead.org; Thu, 10 Apr 2008 14:14:05 +0000 From: Arnd Bergmann To: joern@logfs.org Subject: Re: [patch 4/15] fs/logfs/compr.c Date: Thu, 10 Apr 2008 16:13:47 +0200 References: <20080401181308.512473173@logfs.org> <20080401181332.853833004@logfs.org> In-Reply-To: <20080401181332.853833004@logfs.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200804101613.48465.arnd@arndb.de> Cc: linux-fsdevel@vger.kernel.org, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tuesday 01 April 2008, joern@logfs.org wrote: > + > +static DEFINE_MUTEX(compr_mutex); > +static struct z_stream_s stream; > + How much time is spent in the compression code? Would it be helpful to have a percpu stream and do preempt_disable around it instead of the mutex? That would improve parallelism and cache-locality of the compression, at the cost of adding a source of latency to preemptible kernels. Arnd <>< From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757567AbYDJOOT (ORCPT ); Thu, 10 Apr 2008 10:14:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754814AbYDJOOF (ORCPT ); Thu, 10 Apr 2008 10:14:05 -0400 Received: from moutng.kundenserver.de ([212.227.126.183]:51800 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756169AbYDJOOE (ORCPT ); Thu, 10 Apr 2008 10:14:04 -0400 From: Arnd Bergmann To: joern@logfs.org Subject: Re: [patch 4/15] fs/logfs/compr.c Date: Thu, 10 Apr 2008 16:13:47 +0200 User-Agent: KMail/1.9.9 Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mtd@lists.infradead.org References: <20080401181308.512473173@logfs.org> <20080401181332.853833004@logfs.org> In-Reply-To: <20080401181332.853833004@logfs.org> X-Face: I@=L^?./?$U,EK.)V[4*>`zSqm0>65YtkOe>TFD'!aw?7OVv#~5xd\s,[~w]-J!)|%=]>=?utf-8?q?+=0A=09=7EohchhkRGW=3F=7C6=5FqTmkd=5Ft=3FLZC=23Q-=60=2E=60Y=2Ea=5E?= =?utf-8?q?3zb?=) =?utf-8?q?+U-JVN=5DWT=25cw=23=5BYo0=267C=26bL12wWGlZi=0A=09=7EJ=3B=5Cwg?= =?utf-8?q?=3B3zRnz?=,J"CT_)=\H'1/{?SR7GDu?WIopm.HaBG=QYj"NZD_[zrM\Gip^U MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200804101613.48465.arnd@arndb.de> X-Provags-ID: V01U2FsdGVkX18eNtwzDeZ4uGIxijQFxyf4fMAqE9gvjVEjUxJ 8RYvANVqBidx8z9Og0TBS3Q3zEhMA0Zioa0IZBKeiV2wwFjIof sLQMUHksJQmiOP1y3OBzw== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 01 April 2008, joern@logfs.org wrote: > + > +static DEFINE_MUTEX(compr_mutex); > +static struct z_stream_s stream; > + How much time is spent in the compression code? Would it be helpful to have a percpu stream and do preempt_disable around it instead of the mutex? That would improve parallelism and cache-locality of the compression, at the cost of adding a source of latency to preemptible kernels. Arnd <>< From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [patch 4/15] fs/logfs/compr.c Date: Thu, 10 Apr 2008 16:13:47 +0200 Message-ID: <200804101613.48465.arnd@arndb.de> References: <20080401181308.512473173@logfs.org> <20080401181332.853833004@logfs.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: linux-fsdevel@vger.kernel.org, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org To: joern@logfs.org Return-path: In-Reply-To: <20080401181332.853833004@logfs.org> Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-mtd-bounces@lists.infradead.org Errors-To: linux-mtd-bounces+gldm-linux-mtd-36=gmane.org@lists.infradead.org List-Id: linux-fsdevel.vger.kernel.org On Tuesday 01 April 2008, joern@logfs.org wrote: > + > +static DEFINE_MUTEX(compr_mutex); > +static struct z_stream_s stream; > + How much time is spent in the compression code? Would it be helpful to have a percpu stream and do preempt_disable around it instead of the mutex? That would improve parallelism and cache-locality of the compression, at the cost of adding a source of latency to preemptible kernels. Arnd <>< ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/