From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:43491) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TUDzm-00046h-KR for qemu-devel@nongnu.org; Fri, 02 Nov 2012 05:57:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TUDzl-0008Mp-IP for qemu-devel@nongnu.org; Fri, 02 Nov 2012 05:56:58 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43766) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TUDzl-0008Ma-AJ for qemu-devel@nongnu.org; Fri, 02 Nov 2012 05:56:57 -0400 Date: Fri, 2 Nov 2012 15:26:41 +0530 From: Amit Shah Message-ID: <20121102095641.GD10483@amit.redhat.com> References: <20121022111824.GA6916@amit.redhat.com> <1350913800.90009.YahooMailClassic@web163904.mail.gq1.yahoo.com> <20121023125503.GG19977@stefanha-thinkpad.redhat.com> <20121101091918.GA19405@amit.redhat.com> <20121101120410.GC3993@redhat.com> <20121101160721.GA9176@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121101160721.GA9176@redhat.com> Subject: Re: [Qemu-devel] [PATCH] virtio: limit avail bytes lookahead List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: Stefan Hajnoczi , Edivaldo de Araujo Pereira , qemu-devel@nongnu.org, Anthony Liguori , Bug 1066055 <1066055@bugs.launchpad.net> On (Thu) 01 Nov 2012 [18:07:21], Michael S. Tsirkin wrote: > Commit 0d8d7690850eb0cf2b2b60933cf47669a6b6f18f introduced > a regression in virtio-net performance because it looks > into the ring aggressively while we really only care > about a single packet worth of buffers. > To fix, add parameters limiting lookahead, and > use in virtqueue_avail_bytes. > > Signed-off-by: Michael S. Tsirkin > Reported-by: Edivaldo de Araujo Pereira Acked-by: Amit Shah Amit