From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: [RFC PATCHv1 net-next] xen-netback: always fully coalesce guest Rx packets Date: Tue, 20 Jan 2015 11:38:43 +0000 Message-ID: <54BE3E43.3010405@citrix.com> References: <1421157917-31333-1-git-send-email-david.vrabel@citrix.com> <1421753646.10440.228.camel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: , , Wei Liu To: Ian Campbell Return-path: Received: from smtp.citrix.com ([66.165.176.89]:50949 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752000AbbATLiu (ORCPT ); Tue, 20 Jan 2015 06:38:50 -0500 In-Reply-To: <1421753646.10440.228.camel@citrix.com> Sender: netdev-owner@vger.kernel.org List-ID: On 20/01/15 11:34, Ian Campbell wrote: > On Tue, 2015-01-13 at 14:05 +0000, David Vrabel wrote: >> Always fully coalesce guest Rx packets into the minimum number of ring >> slots. Reducing the number of slots per packet has significant >> performance benefits (e.g., 7.2 Gbit/s to 11 Gbit/s in an off-host >> receive test). >> >> However, this does increase the number of grant ops per packet which >> decreases performance with some workloads (intrahost VM to VM) >> /unless/ grant copy has been optimized for adjacent ops with the same >> source or destination (see "grant-table: defer releasing pages >> acquired in a grant copy"[1]). >> >> Do we need to retain the existing path and make the always coalesce >> path conditional on a suitable version of Xen? >> >> [1] http://lists.xen.org/archives/html/xen-devel/2015-01/msg01118.html >> >> Signed-off-by: David Vrabel > > Looks good to me, thanks. Based on that plus the conversation in the > other subthread: > > Acked-by: Ian Campbell Thanks. I'll resend with a better commit message. David