From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Fastabend Subject: Re: [RFC PATCH 12/12] net: sched: pfifo_fast new option to deque multiple pkts Date: Wed, 30 Dec 2015 10:13:16 -0800 Message-ID: <56841EBC.3000102@gmail.com> References: <20151230175000.26257.41532.stgit@john-Precision-Tower-5810> <20151230175530.26257.2642.stgit@john-Precision-Tower-5810> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: john.r.fastabend@intel.com, netdev@vger.kernel.org To: daniel@iogearbox.net, eric.dumazet@gmail.com, jhs@mojatatu.com, aduyck@mirantis.com, brouer@redhat.com, davem@davemloft.net Return-path: Received: from mail-pf0-f182.google.com ([209.85.192.182]:34606 "EHLO mail-pf0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750814AbbL3SNa (ORCPT ); Wed, 30 Dec 2015 13:13:30 -0500 Received: by mail-pf0-f182.google.com with SMTP id e65so92290420pfe.1 for ; Wed, 30 Dec 2015 10:13:30 -0800 (PST) In-Reply-To: <20151230175530.26257.2642.stgit@john-Precision-Tower-5810> Sender: netdev-owner@vger.kernel.org List-ID: On 15-12-30 09:55 AM, John Fastabend wrote: > Now that pfifo_fast is using the alf_queue data structures we can > dequeue multiple skbs and save some overhead. > > This works because the bulk dequeue logic accepts skb lists already. > > Signed-off-by: John Fastabend > --- oops I didn't mean to send this it obviously doesn't work because until you have 8 skbs nothing gets dequeued. This was just a test patch I was looking at for perf numbers. Maybe it provides some insight into how we could build a pfifo_bulk or add an option to pfifo_fast to dequeue multiple pkts at a time. The trick is to sort out how long to wait for packets to build up or possibly just remove this line, + if (this_cpu_ptr(qdisc->cpu_qstats)->qlen < 8) + return NULL; And opportunistically pull packets out at the risk of over-running the driver if those are large skbs. .John