From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCHv2 net-next] cxgb4: Add low latency socket busy_poll support Date: Wed, 04 Feb 2015 23:56:10 -0800 (PST) Message-ID: <20150204.235610.54093520486544328.davem@davemloft.net> References: <1423044172-23586-1-git-send-email-hariprasad@chelsio.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, leedom@chelsio.com, anish@chelsio.com, nirranjan@chelsio.com, kumaras@chelsio.com To: hariprasad@chelsio.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:41971 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750760AbbBEH4L (ORCPT ); Thu, 5 Feb 2015 02:56:11 -0500 In-Reply-To: <1423044172-23586-1-git-send-email-hariprasad@chelsio.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Hariprasad Shenai Date: Wed, 4 Feb 2015 15:32:52 +0530 > cxgb_busy_poll, corresponding to ndo_busy_poll, gets called by the socket > waiting for data. > > With busy_poll enabled, improvement is seen in latency numbers as observed by > collecting netperf TCP_RR numbers. > Below are latency number, with and without busy-poll, in a switched environment > for a particular msg size: > netperf command: netperf -4 -H -l 30 -t TCP_RR -- -r1,1 > Latency without busy-poll: ~16.25 us > Latency with busy-poll : ~08.79 us > > Based on original work by Kumar Sanghvi > > Signed-off-by: Hariprasad Shenai > --- > V2: fix napi poll return value for repoll, thanks to pointers by > Eric Dumazet Applied, thanks.