From mboxrd@z Thu Jan 1 00:00:00 1970 From: Evgeniy Polyakov Subject: Re: 2.6.27-rc8-git7: Reported regressions from 2.6.26 Date: Sun, 5 Oct 2008 16:05:11 +0400 Message-ID: <20081005120511.GA27993@2ka.mipt.ru> References: <200810051302.20896.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "Rafael J. Wysocki" , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, protasnb-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, kernel-testers-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org, cl-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org To: Herbert Xu Return-path: Content-Disposition: inline In-Reply-To: Sender: kernel-testers-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org Hi. On Sun, Oct 05, 2008 at 07:49:31PM +0800, Herbert Xu (herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org) wrote: > Note that 2.6.27 beats 2.6.26 by 30% with bulk traffic over > loopback as opposed to the small packets sent by tbench where > I saw a 5% drop in performance on my machine. > > So I'm not sure whether this should really be classified as > a regression if we limit ourselves to the changes between 26 > and 27. > > The changes prior to 26 seem to be more significant. Yes, that's the point, TSO over loopback for big packets or workload where there packets can be easily combined into big one results in a fair performance improvement, but for small packets it regresses about 5-10 %. And yes, there are yet unresolved changes which caused bigger performance degradation. -- Evgeniy Polyakov