From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH] vhost: wake up worker outside spin_lock Date: Sun, 9 Jun 2013 12:47:01 +0300 Message-ID: <20130609094701.GA14832@redhat.com> References: <51B1E518.1070003@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: jasowang@redhat.com, kvm@vger.kernel.org, netdev@vger.kernel.org To: Qin Chuanyu Return-path: Content-Disposition: inline In-Reply-To: <51B1E518.1070003@huawei.com> Sender: kvm-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Fri, Jun 07, 2013 at 09:50:16PM +0800, Qin Chuanyu wrote: > the wake_up_process func is included by spin_lock/unlock in > vhost_work_queue, > but it could be done outside the spin_lock. > I have test it with kernel 3.0.27 and guest suse11-sp2 using iperf, > the num as below. > original modified > thread_num tp(Gbps) vhost(%) | tp(Gbps) vhost(%) > 1 9.59 28.82 | 9.59 27.49 > 8 9.61 32.92 | 9.62 26.77 > 64 9.58 46.48 | 9.55 38.99 > 256 9.6 63.7 | 9.6 52.59 > > Signed-off-by: Chuanyu Qin > --- > drivers/vhost/vhost.c | 4 +++- > 1 files changed, 3 insertions(+), 1 deletions(-) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index 94dbd25..dcc7a17 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -146,9 +146,11 @@ static inline void vhost_work_queue(struct > vhost_dev *dev, Applied and queued for 3.11, thanks. This patch is malformed because of the wrapped line above. I've applied this by hand, so just FYI, please see Documentation/email-clients.txt for some hints on configuring mail properly. > if (list_empty(&work->node)) { > list_add_tail(&work->node, &dev->work_list); > work->queue_seq++; > + spin_unlock_irqrestore(&dev->work_lock, flags); > wake_up_process(dev->worker); > + } else { > + spin_unlock_irqrestore(&dev->work_lock, flags); > } > - spin_unlock_irqrestore(&dev->work_lock, flags); > } > > void vhost_poll_queue(struct vhost_poll *poll) > -- > 1.7.3.1.msysgit.0 >