From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jakub Kicinski Subject: Re: [PATCH 4/5] virtio_net: add dedicated XDP transmit queues Date: Fri, 18 Nov 2016 18:10:04 -0800 Message-ID: <20161118181004.4c15a6a1@laptop> References: <20161118185517.16137.92123.stgit@john-Precision-Tower-5810> <20161118190041.16137.48399.stgit@john-Precision-Tower-5810> <20161118130953.7bf2d71d@laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: tgraf@suug.ch, shm@cumulusnetworks.com, alexei.starovoitov@gmail.com, daniel@iogearbox.net, davem@davemloft.net, john.r.fastabend@intel.com, netdev@vger.kernel.org, bblanco@plumgrid.com, brouer@redhat.com To: John Fastabend Return-path: Received: from mx3.wp.pl ([212.77.101.9]:38221 "EHLO mx3.wp.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752735AbcKSCK3 (ORCPT ); Fri, 18 Nov 2016 21:10:29 -0500 In-Reply-To: <20161118130953.7bf2d71d@laptop> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, 18 Nov 2016 13:09:53 -0800, Jakub Kicinski wrote: > Looks very cool! :) > > On Fri, 18 Nov 2016 11:00:41 -0800, John Fastabend wrote: > > @@ -1542,12 +1546,34 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog) > > return -EINVAL; > > } > > > > + curr_qp = vi->curr_queue_pairs - vi->xdp_queue_pairs; > > + if (prog) > > + xdp_qp = num_online_cpus(); > > Is num_online_cpus() correct here? Sorry, I don't know the virto_net code, so I'm probably wrong. I was concerned whether the number of cpus can change but also that the cpu mask may be sparse and therefore offsetting by smp_processor_id() into the queue table below could bring trouble. @@ -353,9 +381,15 @@ static u32 do_xdp_prog(struct virtnet_info *vi, switch (act) { case XDP_PASS: return XDP_PASS; + case XDP_TX: + qp = vi->curr_queue_pairs - + vi->xdp_queue_pairs + + smp_processor_id(); + xdp.data = buf + (vi->mergeable_rx_bufs ? 0 : 4); + virtnet_xdp_xmit(vi, qp, &xdp); + return XDP_TX; default: bpf_warn_invalid_xdp_action(act); - case XDP_TX: case XDP_ABORTED: case XDP_DROP: return XDP_DROP;