| Message ID | 530D66AA.5070004@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
----- Original Message ----- > guest kick vhost base on vring flag status and get perfermance improved, > vhost_zerocopy_callback could do this in the same way, as > virtqueue_enable_cb need one more check after change the status of > avail_ring flags, vhost also do the same thing after vhost_enable_notify > > test result list as below: > guest and host: suse11sp3, netperf, intel 2.4GHz > +------+----------+--------+----------+--------+--------+---------+ > | | old | new | > +------+----------+--------+----------+--------+--------+---------+ > | UDP | Gbit/s | PPS |CPU idle% | Gbit/s | PPS |CPU idle%| > | 256 | 0.74805 | 321309 | 87.16 | 0.77933| 334743 | 90.71 | > | 512 | 1.42 | 328475 | 87.03 | 1.44 | 333550 | 90.43 | > | 1024 | 2.79 | 334426 | 89.09 | 2.81 | 336986 | 89.55 | > | 1460 | 3.71 | 316215 | 87.53 | 4.02 | 342325 | 89.58 | > +------+----------+--------+----------+--------+--------+---------+ > > Signed-off-by: Chuanyu Qin <qinchuanyu@huawei.com> > --- > drivers/vhost/net.c | 12 ++++++++++-- > 1 files changed, 10 insertions(+), 2 deletions(-) > > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c > index a0fa5de..3c76b89 100644 > --- a/drivers/vhost/net.c > +++ b/drivers/vhost/net.c > @@ -314,7 +314,8 @@ static void vhost_zerocopy_callback(struct ubuf_info > *ubuf, bool success) > vq->heads[ubuf->desc].len = success ? > VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN; > cnt = vhost_net_ubuf_put(ubufs); > - > + /* make sure len has been updated because handle_tx would use it */ > + smp_wmb(); Hi Chuanyu: Apologize first for my typo in the last comment, should be a smp_mb() here to prevent the used_flags to be checked(read) before updating the len (writing). smp_wmb() can only prevent re-ordering between writes. btw. If you want you patch to be applied for David tree, you need also cc or to netdev. > /* > * Trigger polling thread if guest stopped submitting new buffers: > * in this case, the refcount after decrement will eventually reach 1. > @@ -322,7 +323,8 @@ static void vhost_zerocopy_callback(struct ubuf_info > *ubuf, bool success) > * (the value 16 here is more or less arbitrary, it's tuned to trigger > * less than 10% of times). > */ > - if (cnt <= 1 || !(cnt % 16)) > + if ((!(vq->used_flags & VRING_USED_F_NO_NOTIFY)) > + && (cnt <= 1 || !(cnt % 16))) > vhost_poll_queue(&vq->poll); > > rcu_read_unlock_bh(); > @@ -386,6 +388,12 @@ static void handle_tx(struct vhost_net *net) > vhost_disable_notify(&net->dev, vq); > continue; > } > + /* there might skb been freed between last > + * vhost_zerocopy_signal_used and vhost_enable_notify, > + * so one more check is needed. > + */ > + if (zcopy) > + vhost_zerocopy_signal_used(net, vq); > break; > } > if (in) { > -- > 1.7.3.1.msysgit.0 > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index a0fa5de..3c76b89 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -314,7 +314,8 @@ static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) vq->heads[ubuf->desc].len = success ? VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN; cnt = vhost_net_ubuf_put(ubufs); - + /* make sure len has been updated because handle_tx would use it */ + smp_wmb(); /* * Trigger polling thread if guest stopped submitting new buffers:
guest kick vhost base on vring flag status and get perfermance improved, vhost_zerocopy_callback could do this in the same way, as virtqueue_enable_cb need one more check after change the status of avail_ring flags, vhost also do the same thing after vhost_enable_notify test result list as below: guest and host: suse11sp3, netperf, intel 2.4GHz +------+----------+--------+----------+--------+--------+---------+ | | old | new | +------+----------+--------+----------+--------+--------+---------+ | UDP | Gbit/s | PPS |CPU idle% | Gbit/s | PPS |CPU idle%| | 256 | 0.74805 | 321309 | 87.16 | 0.77933| 334743 | 90.71 | | 512 | 1.42 | 328475 | 87.03 | 1.44 | 333550 | 90.43 | | 1024 | 2.79 | 334426 | 89.09 | 2.81 | 336986 | 89.55 | | 1460 | 3.71 | 316215 | 87.53 | 4.02 | 342325 | 89.58 | +------+----------+--------+----------+--------+--------+---------+ Signed-off-by: Chuanyu Qin <qinchuanyu@huawei.com> --- drivers/vhost/net.c | 12 ++++++++++-- 1 files changed, 10 insertions(+), 2 deletions(-) * in this case, the refcount after decrement will eventually reach 1. @@ -322,7 +323,8 @@ static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) * (the value 16 here is more or less arbitrary, it's tuned to trigger * less than 10% of times). */ - if (cnt <= 1 || !(cnt % 16)) + if ((!(vq->used_flags & VRING_USED_F_NO_NOTIFY)) + && (cnt <= 1 || !(cnt % 16))) vhost_poll_queue(&vq->poll); rcu_read_unlock_bh(); @@ -386,6 +388,12 @@ static void handle_tx(struct vhost_net *net) vhost_disable_notify(&net->dev, vq); continue; } + /* there might skb been freed between last + * vhost_zerocopy_signal_used and vhost_enable_notify, + * so one more check is needed. + */ + if (zcopy) + vhost_zerocopy_signal_used(net, vq); break; } if (in) {