From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: sunvnet and ->xmit_more Date: Tue, 07 Oct 2014 16:46:49 -0400 (EDT) Message-ID: <20141007.164649.587971614591244924.davem@davemloft.net> References: <20141007192922.GA31406@oracle.com> <20141007.153829.1919460115976279645.davem@davemloft.net> <9BB04EDE-1842-4DB0-93BE-5186B2D187AB@oracle.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: sowmini.varadhan@oracle.com, netdev@vger.kernel.org, david.stevens@oracle.com To: Raghuram.Kothakota@oracle.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:48501 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754939AbaJGUqv (ORCPT ); Tue, 7 Oct 2014 16:46:51 -0400 In-Reply-To: <9BB04EDE-1842-4DB0-93BE-5186B2D187AB@oracle.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Raghuram Kothakota Date: Tue, 7 Oct 2014 13:38:07 -0700 > In case of sunvnet, consumer starting as soon as possible would help > as the consumer is slower as it copies the data to local buffers. The recent > change by DLS avoids the copy in the Tx side, so the producer could be > faster than the receiver. If the trigger is sent after n packets, then consumer > will really start after n packets in the ring and it may have lost that much time > to pickup the packets. I agree for the first few TX queue entires, or even just the first, but after that it always pays to defer and decrease the number of hcalls, locks, etc. Play with it, you'll see.