From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH RFC v4 net-next 0/5] virtio_net: enabling tx interrupts Date: Tue, 2 Dec 2014 12:08:07 +0200 Message-ID: <20141202100806.GA8056@redhat.com> References: <1417429028-11971-1-git-send-email-jasowang@redhat.com> <20141201104223.GB16108@redhat.com> <1417490120.4405.2@smtp.corp.redhat.com> <063D6719AE5E284EB5DD2968C1650D6D1CA007CC@AcuExch.aculab.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: "pagupta@redhat.com" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "virtualization@lists.linux-foundation.org" , "davem@davemloft.net" To: David Laight Return-path: Content-Disposition: inline In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6D1CA007CC@AcuExch.aculab.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 List-Id: netdev.vger.kernel.org On Tue, Dec 02, 2014 at 10:00:06AM +0000, David Laight wrote: > From: Jason Wang > > > On Mon, Dec 01, 2014 at 06:17:03PM +0800, Jason Wang wrote: > > >> Hello: > > >> > > >> We used to orphan packets before transmission for virtio-net. This > > >> breaks > > >> socket accounting and can lead serveral functions won't work, e.g: > > >> > > >> - Byte Queue Limit depends on tx completion nofication to work. > > >> - Packet Generator depends on tx completion nofication for the last > > >> transmitted packet to complete. > > >> - TCP Small Queue depends on proper accounting of sk_wmem_alloc to > > >> work. > > >> > > >> This series tries to solve the issue by enabling tx interrupts. To > > >> minize > > >> the performance impacts of this, several optimizations were used: > > >> > > >> - In guest side, virtqueue_enable_cb_delayed() was used to delay the tx > > >> interrupt untile 3/4 pending packets were sent. > > Doesn't that give problems for intermittent transmits? > > ... > > David > No because it has not effect in that case. -- MST