On Fri, Jun 7, 2013 at 9:50 PM, Qin Chuanyu <qinchuanyu@xxxxxxxxxx> 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 <qinchuanyu@xxxxxxxxxx>
> ---
> 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,
>
> 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);
>
> }
Hmm, this looks more clearer to me.
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -156,14 +156,17 @@ EXPORT_SYMBOL_GPL(vhost_poll_flush);
void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work)
{
unsigned long flags;
+ bool wakeup = false;
spin_lock_irqsave(&dev->work_lock, flags);
if (list_empty(&work->node)) {
list_add_tail(&work->node, &dev->work_list);
work->queue_seq++;
- wake_up_process(dev->worker);
+ wakeup = true;
}
spin_unlock_irqrestore(&dev->work_lock, flags);
+ if (wakeup)
+ wake_up_process(dev->worker);
}
>
> void vhost_poll_queue(struct vhost_poll *poll)
> --
> 1.7.3.1.msysgit.0
>
>
> --
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--
Asias
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