From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rusty Russell Subject: Re: [PATCHv2 10/14] virtio_net: limit xmit polling Date: Wed, 25 May 2011 11:05:04 +0930 Message-ID: <8739k3k1fb.fsf__14510.109430603$1306298827$gmane$org@rustcorp.com.au> References: <877h9kvlps.fsf@rustcorp.com.au> <20110522121008.GA12155@redhat.com> <87boyutbjg.fsf@rustcorp.com.au> <20110523111900.GB27212@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20110523111900.GB27212@redhat.com> 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 To: "Michael S. Tsirkin" Cc: Krishna Kumar , Carsten Otte , lguest@lists.ozlabs.org, Shirley Ma , kvm@vger.kernel.org, linux-s390@vger.kernel.org, netdev@vger.kernel.org, habanero@linux.vnet.ibm.com, Heiko Carstens , linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, steved@us.ibm.com, Christian Borntraeger , Tom Lendacky , Martin Schwidefsky , linux390@de.ibm.com List-Id: virtualization@lists.linuxfoundation.org On Mon, 23 May 2011 14:19:00 +0300, "Michael S. Tsirkin" wrote: > I do understand how it seems a waste to leave direct space > in the ring while we might in practice have space > due to indirect. Didn't come up with a nice way to > solve this yet - but 'no worse than now :)' Let's just make it "bool free_old_xmit_skbs(unsigned int max)". max == 2 for the normal xmit path, so we're low latency but we keep ahead on average. max == -1 for the "we're out of capacity, we may have to stop the queue". That keeps it simple and probably the right thing... Thanks, Rusty.