Re: [PATCH] vhost: get 2% performance improved by reducing spin_lock race in vhost_work_queue
From: Chuanyu Qin
Subject: [PATCH] get 2% or more performance improved by reducing spin_lock race
in vhost_work_queue
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.
orignal modified
thread_num tp(Gbps) vhost(%) | tp(Gbps) vhost(%)
1 9.59 28.82 | 9.5927.49
89.6132.92 | 9.6226.77
649.5846.48 | 9.5538.99
2569.663.7 | 9.6 52.59
Signed-off-by: Chuanyu Qin
---
drivers/vhost/vhost.c |5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 94dbd25..8bee109 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -146,9 +146,10 @@ 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);
- }
- spin_unlock_irqrestore(&dev->work_lock, flags);
+ } else
+ spin_unlock_irqrestore(&dev->work_lock, flags);
}
void vhost_poll_queue(struct vhost_poll *poll)
--
1.7.3.1.msysgit.0
> On 05/20/2013 12:22 PM, Qinchuanyu wrote:
> > The patch below is base on
> > https://git.kernel.org/cgit/linux/kernel/git/next/linux-
> next.git/tree/drivers/vhost/vhost.c?id=refs/tags/next-20130517
> >
> > Signed-off-by: Chuanyu Qin
> > --- a/drivers/vhost/vhost.c 2013-05-20 11:47:05.0 +0800
> > +++ b/drivers/vhost/vhost.c 2013-05-20 11:48:24.0 +0800
> > @@ -154,9 +154,10 @@
> > 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);
> > - }
> > - spin_unlock_irqrestore(&dev->work_lock, flags);
> > + } else
> > + spin_unlock_irqrestore(&dev->work_lock, flags);
> > }
> >
> > void vhost_poll_queue(struct vhost_poll *poll)
> >
> > I did the test by using iperf in 10G environment, the test num as
> below:
> > orignal modified
> > thread_num tp(Gbps) vhost(%) | tp(Gbps) vhost(%)
> > 1 9.59 28.82 | 9.5927.49
> > 89.6132.92 | 9.6226.77
> > 649.5846.48 | 9.5538.99
> > 2569.663.7 | 9.6 52.59
> >
> > The cost of vhost reduced while the throughput is almost unchanged.
>
> Thanks, and please generate a formal patch based on
> Documentation/SubmittingPatches (put the description and perf numbers
> in the commit log). Then resubmit it to let the maintainer apply it.
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Re: [PATCH] vhost: get 2% performance improved by reducing spin_lock race in vhost_work_queue
On 05/20/2013 12:22 PM, Qinchuanyu wrote:
> The patch below is base on
> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/tree/drivers/vhost/vhost.c?id=refs/tags/next-20130517
>
> Signed-off-by: Chuanyu Qin
> --- a/drivers/vhost/vhost.c 2013-05-20 11:47:05.0 +0800
> +++ b/drivers/vhost/vhost.c 2013-05-20 11:48:24.0 +0800
> @@ -154,9 +154,10 @@
> 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);
> - }
> - spin_unlock_irqrestore(&dev->work_lock, flags);
> + } else
> + spin_unlock_irqrestore(&dev->work_lock, flags);
> }
>
> void vhost_poll_queue(struct vhost_poll *poll)
>
> I did the test by using iperf in 10G environment, the test num as below:
> orignal modified
> thread_num tp(Gbps) vhost(%) | tp(Gbps) vhost(%)
> 1 9.59 28.82 | 9.5927.49
> 89.6132.92 | 9.6226.77
> 649.5846.48 | 9.5538.99
> 2569.663.7 | 9.6 52.59
>
> The cost of vhost reduced while the throughput is almost unchanged.
Thanks, and please generate a formal patch based on
Documentation/SubmittingPatches (put the description and perf numbers in
the commit log). Then resubmit it to let the maintainer apply it.
>
> On 05/20/2013 11:06 AM, Qinchuanyu wrote:
>> Right now the wake_up_process func is included in spin_lock/unlock, but it
>> could be done outside the spin_lock.
>> I have test it with kernel 3.0.27 and guest suse11-sp2, it provide 2%-3% net
>> performance improved.
>>
>> Signed-off-by: Chuanyu Qin
> Make sense to me but need generate a patch against net-next.git or
> vhost.git in git.kernel.org.
>
> Btw. How did you test this? Care to share the perf numbers?
>
> Thanks
>> mu
>> --- a/drivers/vhost/vhost.c 2013-05-20 10:36:30.0 +0800
>> +++ b/drivers/vhost/vhost.c 2013-05-20 10:36:54.0 +0800
>> @@ -144,9 +144,10 @@
>> 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);
>> - }
>> - spin_unlock_irqrestore(&dev->work_lock, flags);
>> + } else
>> + spin_unlock_irqrestore(&dev->work_lock, flags);
>> }
>>
>> void vhost_poll_queue(struct vhost_poll *poll)
>> --
>> To unsubscribe from this list: send the line "unsubscribe netdev" in
>> the body of a message to majord...@vger.kernel.org
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
> N�r��y���b�X��ǧv�^�){.n�+���z�^�)���w* jg��� �ݢj/���z�ޖ��2�ޙ���&�)ߡ�a���� �G���h��j:+v���w�٥
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Re: [PATCH] vhost: get 2% performance improved by reducing spin_lock race in vhost_work_queue
The patch below is base on
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/tree/drivers/vhost/vhost.c?id=refs/tags/next-20130517
Signed-off-by: Chuanyu Qin
--- a/drivers/vhost/vhost.c 2013-05-20 11:47:05.0 +0800
+++ b/drivers/vhost/vhost.c 2013-05-20 11:48:24.0 +0800
@@ -154,9 +154,10 @@
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);
- }
- spin_unlock_irqrestore(&dev->work_lock, flags);
+ } else
+ spin_unlock_irqrestore(&dev->work_lock, flags);
}
void vhost_poll_queue(struct vhost_poll *poll)
I did the test by using iperf in 10G environment, the test num as below:
orignal modified
thread_num tp(Gbps) vhost(%) | tp(Gbps) vhost(%)
1 9.59 28.82 | 9.5927.49
89.6132.92 | 9.6226.77
649.5846.48 | 9.5538.99
2569.663.7 | 9.6 52.59
The cost of vhost reduced while the throughput is almost unchanged.
On 05/20/2013 11:06 AM, Qinchuanyu wrote:
> Right now the wake_up_process func is included in spin_lock/unlock, but it
> could be done outside the spin_lock.
> I have test it with kernel 3.0.27 and guest suse11-sp2, it provide 2%-3% net
> performance improved.
>
> Signed-off-by: Chuanyu Qin
Make sense to me but need generate a patch against net-next.git or
vhost.git in git.kernel.org.
Btw. How did you test this? Care to share the perf numbers?
Thanks
> mu
> --- a/drivers/vhost/vhost.c 2013-05-20 10:36:30.0 +0800
> +++ b/drivers/vhost/vhost.c 2013-05-20 10:36:54.0 +0800
> @@ -144,9 +144,10 @@
> 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);
> - }
> - spin_unlock_irqrestore(&dev->work_lock, flags);
> + } else
> + spin_unlock_irqrestore(&dev->work_lock, flags);
> }
>
> void vhost_poll_queue(struct vhost_poll *poll)
> --
> To unsubscribe from this list: send the line "unsubscribe netdev" in
> the body of a message to majord...@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] vhost: get 2% performance improved by reducing spin_lock race in vhost_work_queue
On 05/20/2013 11:38 AM, Jason Wang wrote:
On 05/20/2013 11:06 AM, Qinchuanyu wrote:
Right now the wake_up_process func is included in spin_lock/unlock, but it
could be done outside the spin_lock.
I have test it with kernel 3.0.27 and guest suse11-sp2, it provide 2%-3% net
performance improved.
Signed-off-by: Chuanyu Qin
Make sense to me but need generate a patch against net-next.git or
vhost.git in git.kernel.org.
Btw. How did you test this? Care to share the perf numbers?
I wonder how did you get the performance improved number 2%?
Thanks
mu
--- a/drivers/vhost/vhost.c 2013-05-20 10:36:30.0 +0800
+++ b/drivers/vhost/vhost.c 2013-05-20 10:36:54.0 +0800
@@ -144,9 +144,10 @@
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);
- }
- spin_unlock_irqrestore(&dev->work_lock, flags);
+ } else
+ spin_unlock_irqrestore(&dev->work_lock, flags);
}
void vhost_poll_queue(struct vhost_poll *poll)
--
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Re: [PATCH] vhost: get 2% performance improved by reducing spin_lock race in vhost_work_queue
On 05/20/2013 11:06 AM, Qinchuanyu wrote:
> Right now the wake_up_process func is included in spin_lock/unlock, but it
> could be done outside the spin_lock.
> I have test it with kernel 3.0.27 and guest suse11-sp2, it provide 2%-3% net
> performance improved.
>
> Signed-off-by: Chuanyu Qin
Make sense to me but need generate a patch against net-next.git or
vhost.git in git.kernel.org.
Btw. How did you test this? Care to share the perf numbers?
Thanks
> mu
> --- a/drivers/vhost/vhost.c 2013-05-20 10:36:30.0 +0800
> +++ b/drivers/vhost/vhost.c 2013-05-20 10:36:54.0 +0800
> @@ -144,9 +144,10 @@
> 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);
> - }
> - spin_unlock_irqrestore(&dev->work_lock, flags);
> + } else
> + spin_unlock_irqrestore(&dev->work_lock, flags);
> }
>
> void vhost_poll_queue(struct vhost_poll *poll)
> --
> To unsubscribe from this list: send the line "unsubscribe netdev" in
> the body of a message to majord...@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
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[PATCH] vhost: get 2% performance improved by reducing spin_lock race in vhost_work_queue
Right now the wake_up_process func is included in spin_lock/unlock, but it
could be done outside the spin_lock.
I have test it with kernel 3.0.27 and guest suse11-sp2, it provide 2%-3% net
performance improved.
Signed-off-by: Chuanyu Qin
--- a/drivers/vhost/vhost.c 2013-05-20 10:36:30.0 +0800
+++ b/drivers/vhost/vhost.c 2013-05-20 10:36:54.0 +0800
@@ -144,9 +144,10 @@
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);
- }
- spin_unlock_irqrestore(&dev->work_lock, flags);
+ } else
+ spin_unlock_irqrestore(&dev->work_lock, flags);
}
void vhost_poll_queue(struct vhost_poll *poll)
--
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