From: Eric Sandeen Subject: Re: [PATCH v3 0/2] ext4: increase mbcache scalability Date: Sat, 19 Oct 2013 18:06:27 -0500 Message-ID: <52631073.3060503@redhat.com> References: <52309F27.8060008@redhat.com> <5230D739.9010109@redhat.com> <20130911212523.GE13397@thunk.org> <5230D450.7000609@hp.com> <20130912122317.GC12918@thunk.org> <5232FF3E.7080604@hp.com> <5233609F.7060303@redhat.com> <523886CE.2070203@hp.com> <5239B65E.4060202@redhat.com> <20130921185304.GB8606@thunk.org> <52432EB5.1090706@hp.com> <52612CE6.9080609@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Andreas Dilger , "Theodore Ts'o" , "linux-ext4@vger.kernel.org List" , "Chandramouleeswaran, Aswin" , Linus Torvalds To: Thavatchai Makphaibulchoke Return-path: Received: from mx1.redhat.com ([209.132.183.28]:2497 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750767Ab3JSXGy (ORCPT ); Sat, 19 Oct 2013 19:06:54 -0400 In-Reply-To: <52612CE6.9080609@hp.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 10/18/13 7:43 AM, Thavatchai Makphaibulchoke wrote: > On 10/03/2013 09:22 PM, Andreas Dilger wrote: > >> >> This is a pretty significant price to pay for SELinux in any case. >> I guess it is probably lower overhead with 256-byte inodes, but >> anything that adds 5-25% overhead shouldn't be taken for granted. >> >> Cheers, Andreas >> > > So far we have determined that, > > - With SELinux enabled a ramdisk filesytem, with default node size of 128 bytes, extended xattr is generated > - In one of the aim7 workload, mbcache has a hit ratio of about 65% > > Seems like mbcache itself and the mbcache lock optimization attempt > by the patch could actually improve performance for a real word > system where extended xattr is employed. I believe the patch should > go in if there isn't any concern. But the 128-byte inode size is not common, so in general, mbcache isn't exercised that often. (still, it is there, and if there's a nice scalability patch for it, it's probably worth it). -Eric > Please let me know if there is any comment or concern about the patch. > > Thanks, > Mak. > > >