From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: [PATCH net-next 2/2] virtio-net: coalesce rx frags when possible during rx Date: Fri, 01 Nov 2013 13:37:02 +0800 Message-ID: <52733DFE.7090704@redhat.com> References: <1383215313-23651-1-git-send-email-jasowang@redhat.com> <1383215313-23651-2-git-send-email-jasowang@redhat.com> <87iowcc1id.fsf@rustcorp.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Rusty Russell , davem@davemloft.net, edumazet@google.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, mst@redhat.com, mwdalton@google.com, virtualization@lists.linux-foundation.org Return-path: In-Reply-To: <87iowcc1id.fsf@rustcorp.com.au> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org List-Id: netdev.vger.kernel.org On 11/01/2013 10:13 AM, Rusty Russell wrote: > Jason Wang writes: >> Commit 2613af0ed18a11d5c566a81f9a6510b73180660a (virtio_net: migrate mergeable >> rx buffers to page frag allocators) try to increase the payload/truesize for >> MTU-sized traffic. But this will introduce the extra overhead for GSO packets >> received because of the frag list. This commit tries to reduce this issue by >> coalesce the possible rx frags when possible during rx. Test result shows the >> about 15% improvement on full size GSO packet receiving (and even better than >> commit 2613af0ed18a11d5c566a81f9a6510b73180660a). > I don't know about the other users of skb_add_rx_frag, but should > this coalesce-if-possible code be built into that? There're several other users without the possibility check. And Eric point out in do_tcp_sendpages() skb_add_rx_frag() and skb_can_coalesce() were used separatedly which can allows us to do some other things in the middle. So it was ok here. > > Thanks, > Rusty.