Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934108AbZKYCQQ (ORCPT ); Tue, 24 Nov 2009 21:16:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758229AbZKYCQP (ORCPT ); Tue, 24 Nov 2009 21:16:15 -0500 Received: from e4.ny.us.ibm.com ([32.97.182.144]:40470 "EHLO e4.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758217AbZKYCQP (ORCPT ); Tue, 24 Nov 2009 21:16:15 -0500 Subject: Re: -rt dbench scalabiltiy issue From: john stultz To: Nick Piggin Cc: Ingo Molnar , Thomas Gleixner , Darren Hart , Clark Williams , "Paul E. McKenney" , Dinakar Guniguntala , lkml In-Reply-To: <20091123090630.GF5602@wotan.suse.de> References: <1255723519.5135.121.camel@localhost.localdomain> <20091017223902.GA29439@wotan.suse.de> <1258507696.2077.61.camel@localhost> <20091118042516.GC21813@wotan.suse.de> <1258683764.3840.28.camel@localhost.localdomain> <20091123090630.GF5602@wotan.suse.de> Content-Type: text/plain; charset="ISO-8859-1" Date: Tue, 24 Nov 2009 18:16:17 -0800 Message-ID: <1259115377.2115.25.camel@localhost> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4483 Lines: 78 On Mon, 2009-11-23 at 10:06 +0100, Nick Piggin wrote: > BTW. Have you tested like ext4, xfs and btrfs cases? I don't think ext3 > is likely to see a huge amount of scalability work, and so it will be > good to give an early heads up to the more active projects... Yea, I need to give those a shot. I also generated the same numbers as before with ext2 (all the raw numbers are in dbench-scalability dir): http://sr71.net/~jstultz/dbench-scalability/graphs/ext2-scalability.png Again, its similar to ext3, in that all the -rt variants are hitting some contention issues. But I was a little surprised to see 2.6.32-rc7-nick below 2.6.32-rc7 there, so generated perf data there as well: http://sr71.net/~jstultz/dbench-scalability/perflogs/2.6.32-rc7-nick.ext2.perflog 31.91% dbench [kernel] [k] _spin_lock | |--44.17%-- dput | | | |--50.39%-- __link_path_walk | | | | | |--99.88%-- path_walk | | | | | | | |--96.18%-- do_path_lookup | | | | | | | | | |--51.49%-- user_path_at | | | | | | | | | | | |--96.84%-- vfs_fstatat | | | | | | vfs_stat | | | | | | sys_newstat | | | | | | system_call_fastpath | | | | | | _xstat | | | | | | | | | | | --3.16%-- do_utimes | | | | | sys_utime | | | | | system_call_fastpath | | | | | __GI_utime | | | | | | | | | |--43.18%-- do_filp_open | | | | | do_sys_open | | | | | sys_open | | | | | system_call_fastpath | | | | | __GI___open ... |--39.98%-- path_get | | | |--51.19%-- path_init | | | | | |--96.40%-- do_path_lookup | | | | | | | |--55.12%-- user_path_at | | | | | | | | | |--91.47%-- vfs_fstatat | | | | | vfs_stat | | | | | sys_newstat | | | | | system_call_fastpath | | | | | _xstat | | | | | | | | | | | --100.00%-- 0x7478742e746e65 | | | | | So I'm a little confused here. Why is dput/path_get showing up in ext2 when it all but disappeared with ramfs? Does ramfs have some sort of vfs_stat shortcut that avoids whatever is catching us here? thanks -john -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/