From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [RFC] napi: limit GRO latency Date: Mon, 8 Oct 2012 12:12:48 -0700 Message-ID: <20121008121248.783e6dc4@nehalam.linuxnetplumber.net> References: <1349718955.21172.3534.camel@edumazet-glaptop> <1349719006.21172.3537.camel@edumazet-glaptop> <20121008115835.3a3bfed6@nehalam.linuxnetplumber.net> <20121008.151035.1665672334154033755.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: eric.dumazet@gmail.com, rick.jones2@hp.com, herbert@gondor.apana.org.au, netdev@vger.kernel.org, jesse@nicira.com To: David Miller Return-path: Received: from mail.vyatta.com ([76.74.103.46]:42108 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753498Ab2JHTNb (ORCPT ); Mon, 8 Oct 2012 15:13:31 -0400 In-Reply-To: <20121008.151035.1665672334154033755.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 08 Oct 2012 15:10:35 -0400 (EDT) David Miller wrote: > From: Stephen Hemminger > Date: Mon, 8 Oct 2012 11:58:35 -0700 > > > Limit the latency of pending GRO in NAPI processing to 2*HZ. > > When the system is under heavy network load, NAPI will go into > > poll mode via soft irq, and only stay in the loop for > > two jiffies. If this occurs, process the GRO pending list > > to make sure and not delay outstanding TCP frames for too long. > > > > Rearrange the exit path to get rid of unnecessary goto logic. > > > > Signed-off-by: Stephen Hemminger > > Did you see Eric's patch I just applied which limits it to 1ms? Think this is a different problem. After leaving softirq, it may be a long time until ksoftirqd is run which is a different problem.