From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH] vmxnet3: cap copy length at size of skb to prevent dropped frames on tx Date: Sun, 19 Feb 2012 18:58:52 -0500 (EST) Message-ID: <20120219.185852.396438198148869233.davem@davemloft.net> References: <1329392936-14548-1-git-send-email-nhorman@tuxdriver.com> <19987954.351014.1329422822704.JavaMail.root@zimbra-prod-mbox-5.vmware.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: nhorman@tuxdriver.com, mmatveev@redhat.com, pv-drivers@vmware.com, netdev@vger.kernel.org To: sbhatewara@vmware.com Return-path: Received: from shards.monkeyblade.net ([198.137.202.13]:40637 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751589Ab2BSX77 (ORCPT ); Sun, 19 Feb 2012 18:59:59 -0500 In-Reply-To: <19987954.351014.1329422822704.JavaMail.root@zimbra-prod-mbox-5.vmware.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Shreyas Bhatewara Date: Thu, 16 Feb 2012 12:07:02 -0800 (PST) > >> Also, since I'm unable to do this, it wuold be great if vmware could >> follow up >> this patch with some additional code commentary as to why 54 bytes is >> an optimal >> pull length for a virtual NIC driver. The comment that introduced >> this was >> vague on that. Thanks! > > > Neil, thanks for the patch. We fixed this bug in local repositories > recently and I was about to post a patch to LKML. As for the explanation, > the vNIC is optimized to work with most frequently occurring headers(TCP) > and hence needs particular number of bytes in first sg. Even in case of > UDP this pull is cheaper (CPU utilization wise) to do in guest than in > device emulation. > > Signed-off-by: Shreyas N Bhatewara Applied.