From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932069Ab2GXIcV (ORCPT ); Tue, 24 Jul 2012 04:32:21 -0400 Received: from mailout-de.gmx.net ([213.165.64.23]:54333 "HELO mailout-de.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1755763Ab2GXIcR (ORCPT ); Tue, 24 Jul 2012 04:32:17 -0400 X-Authenticated: #14349625 X-Provags-ID: V01U2FsdGVkX187e2JO2xs7e4qF3XqgmSoaK9MvIlRdibZrxuV/hq dV59XhIkM/Rgv2 Message-ID: <1343118731.7412.72.camel@marge.simpson.net> Subject: Re: [MMTests] Sysbench read-only on ext3 From: Mike Galbraith To: Mel Gorman Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org Date: Tue, 24 Jul 2012 10:32:11 +0200 In-Reply-To: <20120724081903.GL9222@suse.de> References: <20120620113252.GE4011@suse.de> <20120629111932.GA14154@suse.de> <20120723211334.GA9222@suse.de> <1343096969.7412.21.camel@marge.simpson.net> <20120724081903.GL9222@suse.de> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2012-07-24 at 09:19 +0100, Mel Gorman wrote: > On Tue, Jul 24, 2012 at 04:29:29AM +0200, Mike Galbraith wrote: > > On Mon, 2012-07-23 at 22:13 +0100, Mel Gorman wrote: > > > > > The backing database was postgres. > > > > FWIW, that wouldn't have been my choice. I don't know if it still does, > > but it used to use userland spinlocks to achieve scalability. > > The tests used to support mysql but the code bit-rotted and eventually > got deleted. I'm not going to get into a mysql vs postgres discussion on > which is better :O > > Were you thinking of mysql or something else as an alternative? > Completely different test? Which db is under the hood doesn't matter much, but those spinlocks got me thinking. > > Turning > > your CPUs into space heaters to combat concurrency issues makes a pretty > > flat graph, but probably doesn't test kernels as well as something that > > did not do that. > > > > I did not check the source, but even if it is true then your comments only > applies to testing scalability of locking. If someone really cares to check, > the postgres version was 9.0.4. However, even if they are using user-space > locking, the test is still useful for looking at the IO performance, > page reclaim decisions and so on. I was thinking while you're spinning in userspace, you're not giving the kernel decisions to make. But you're right. If they didn't have spinning locks, they'd have sleeping locks. With spinning locks they can be less smart I suppose. -Mike From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx175.postini.com [74.125.245.175]) by kanga.kvack.org (Postfix) with SMTP id 6D7DB6B005A for ; Tue, 24 Jul 2012 04:32:14 -0400 (EDT) Message-ID: <1343118731.7412.72.camel@marge.simpson.net> Subject: Re: [MMTests] Sysbench read-only on ext3 From: Mike Galbraith Date: Tue, 24 Jul 2012 10:32:11 +0200 In-Reply-To: <20120724081903.GL9222@suse.de> References: <20120620113252.GE4011@suse.de> <20120629111932.GA14154@suse.de> <20120723211334.GA9222@suse.de> <1343096969.7412.21.camel@marge.simpson.net> <20120724081903.GL9222@suse.de> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org On Tue, 2012-07-24 at 09:19 +0100, Mel Gorman wrote: > On Tue, Jul 24, 2012 at 04:29:29AM +0200, Mike Galbraith wrote: > > On Mon, 2012-07-23 at 22:13 +0100, Mel Gorman wrote: > > > > > The backing database was postgres. > > > > FWIW, that wouldn't have been my choice. I don't know if it still does, > > but it used to use userland spinlocks to achieve scalability. > > The tests used to support mysql but the code bit-rotted and eventually > got deleted. I'm not going to get into a mysql vs postgres discussion on > which is better :O > > Were you thinking of mysql or something else as an alternative? > Completely different test? Which db is under the hood doesn't matter much, but those spinlocks got me thinking. > > Turning > > your CPUs into space heaters to combat concurrency issues makes a pretty > > flat graph, but probably doesn't test kernels as well as something that > > did not do that. > > > > I did not check the source, but even if it is true then your comments only > applies to testing scalability of locking. If someone really cares to check, > the postgres version was 9.0.4. However, even if they are using user-space > locking, the test is still useful for looking at the IO performance, > page reclaim decisions and so on. I was thinking while you're spinning in userspace, you're not giving the kernel decisions to make. But you're right. If they didn't have spinning locks, they'd have sleeping locks. With spinning locks they can be less smart I suppose. -Mike -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org