search for: chuanyu

On 02/26/2014 02:32 PM, Qin Chuanyu wrote: > On 2014/2/26 13:53, Jason Wang wrote: >> On 02/25/2014 09:57 PM, Michael S. Tsirkin wrote: >>> On Tue, Feb 25, 2014 at 02:53:58PM +0800, Jason Wang wrote: >>>> We used to stop the handling of tx when the number of pending DMAs >>>> exceeds VHOST_MA...

On 02/26/2014 02:32 PM, Qin Chuanyu wrote: > On 2014/2/26 13:53, Jason Wang wrote: >> On 02/25/2014 09:57 PM, Michael S. Tsirkin wrote: >>> On Tue, Feb 25, 2014 at 02:53:58PM +0800, Jason Wang wrote: >>>> We used to stop the handling of tx when the number of pending DMAs >>>> exceeds VHOST_MA...

...CPU utilization is 16% Completed performance test on 40gbe shows no obvious changes in both throughput and cpu utilization with this patch. The patch only solve this issue when unlimited sndbuf. We still need a solution for limited sndbuf. Cc: Michael S. Tsirkin <mst at redhat.com> Cc: Qin Chuanyu <qinchuanyu at huawei.com> Signed-off-by: Jason Wang <jasowang at redhat.com> --- Changes from V1: - Remove VHOST_MAX_PEND and switch to use half of the vq size as the limit - Add cpu utilization in commit log --- drivers/vhost/net.c | 19 +++++++------------ 1 file changed, 7 insertio...

...CPU utilization is 16% Completed performance test on 40gbe shows no obvious changes in both throughput and cpu utilization with this patch. The patch only solve this issue when unlimited sndbuf. We still need a solution for limited sndbuf. Cc: Michael S. Tsirkin <mst at redhat.com> Cc: Qin Chuanyu <qinchuanyu at huawei.com> Signed-off-by: Jason Wang <jasowang at redhat.com> --- Changes from V1: - Remove VHOST_MAX_PEND and switch to use half of the vq size as the limit - Add cpu utilization in commit log --- drivers/vhost/net.c | 19 +++++++------------ 1 file changed, 7 insertio...

On 02/26/2014 05:23 PM, Michael S. Tsirkin wrote: > On Wed, Feb 26, 2014 at 03:11:21PM +0800, Jason Wang wrote: >> > On 02/26/2014 02:32 PM, Qin Chuanyu wrote: >>> > >On 2014/2/26 13:53, Jason Wang wrote: >>>> > >>On 02/25/2014 09:57 PM, Michael S. Tsirkin wrote: >>>>> > >>>On Tue, Feb 25, 2014 at 02:53:58PM +0800, Jason Wang wrote: >>>>>> > >>>>We used...

On 02/26/2014 05:23 PM, Michael S. Tsirkin wrote: > On Wed, Feb 26, 2014 at 03:11:21PM +0800, Jason Wang wrote: >> > On 02/26/2014 02:32 PM, Qin Chuanyu wrote: >>> > >On 2014/2/26 13:53, Jason Wang wrote: >>>> > >>On 02/25/2014 09:57 PM, Michael S. Tsirkin wrote: >>>>> > >>>On Tue, Feb 25, 2014 at 02:53:58PM +0800, Jason Wang wrote: >>>>>> > >>>>We used...

On 08/31/2013 12:45 PM, Qin Chuanyu wrote: > On 2013/8/30 0:08, Anthony Liguori wrote: >> Hi Qin, > >>> By change the memory copy and notify mechanism ，currently >>> virtio-net with >>> vhost_net could run on Xen with good performance。 >> >> I think the key in doing this would be to...

...e (which is on VM shotdown so might happen after a looooong time). Let's do what we probably should have done straight away: switch from kref to plain atomic, documenting the semantics, return the refcount value atomically after decrement, then use that to avoid the deadlock. Reported-by: Qin Chuanyu <qinchuanyu at huawei.com> Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- This patch is needed for 3.14 and -stable. drivers/vhost/net.c | 41 ++++++++++++++++++++--------------------- 1 file changed, 20 insertions(+), 21 deletions(-) diff --git a/drivers/vhost/net.c b/dr...

...e (which is on VM shotdown so might happen after a looooong time). Let's do what we probably should have done straight away: switch from kref to plain atomic, documenting the semantics, return the refcount value atomically after decrement, then use that to avoid the deadlock. Reported-by: Qin Chuanyu <qinchuanyu at huawei.com> Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- This patch is needed for 3.14 and -stable. drivers/vhost/net.c | 41 ++++++++++++++++++++--------------------- 1 file changed, 20 insertions(+), 21 deletions(-) diff --git a/drivers/vhost/net.c b/dr...

...rformance test on 40gbe shows no obvious changes in >> throughput after this patch. >> >> The patch only solve this issue when unlimited sndbuf. We still need a >> solution for limited sndbuf. >> >> Cc: Michael S. Tsirkin<mst at redhat.com> >> Cc: Qin Chuanyu<qinchuanyu at huawei.com> >> Signed-off-by: Jason Wang<jasowang at redhat.com> > I think this needs some thought. > > In particular I think this works because VHOST_MAX_PEND > is much smaller than the ring size. > Shouldn't max_pend then be tied to the ring size...

...rformance test on 40gbe shows no obvious changes in >> throughput after this patch. >> >> The patch only solve this issue when unlimited sndbuf. We still need a >> solution for limited sndbuf. >> >> Cc: Michael S. Tsirkin<mst at redhat.com> >> Cc: Qin Chuanyu<qinchuanyu at huawei.com> >> Signed-off-by: Jason Wang<jasowang at redhat.com> > I think this needs some thought. > > In particular I think this works because VHOST_MAX_PEND > is much smaller than the ring size. > Shouldn't max_pend then be tied to the ring size...

On Wed, Feb 26, 2014 at 03:11:21PM +0800, Jason Wang wrote: > On 02/26/2014 02:32 PM, Qin Chuanyu wrote: > >On 2014/2/26 13:53, Jason Wang wrote: > >>On 02/25/2014 09:57 PM, Michael S. Tsirkin wrote: > >>>On Tue, Feb 25, 2014 at 02:53:58PM +0800, Jason Wang wrote: > >>>>We used to stop the handling of tx when the number of pending DMAs > >>>...

On 2013/8/30 12:29, Jason Wang wrote: > We used to poll vhost queue before making DMA is done, this is racy if vhost > thread were waked up before marking DMA is done which can result the signal to > be missed. Fix this by always poll the vhost thread before DMA is done. > > Signed-off-by: Jason Wang <jasowang at redhat.com> > --- > drivers/vhost/net.c | 9 +++++----

On 2013/8/30 12:29, Jason Wang wrote: > We used to poll vhost queue before making DMA is done, this is racy if vhost > thread were waked up before marking DMA is done which can result the signal to > be missed. Fix this by always poll the vhost thread before DMA is done. > > Signed-off-by: Jason Wang <jasowang at redhat.com> > --- > drivers/vhost/net.c | 9 +++++----

...9.3Mbit/s Vm1 to External throughput is 93Mbit/s Simple performance test on 40gbe shows no obvious changes in throughput after this patch. The patch only solve this issue when unlimited sndbuf. We still need a solution for limited sndbuf. Cc: Michael S. Tsirkin <mst at redhat.com> Cc: Qin Chuanyu <qinchuanyu at huawei.com> Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/vhost/net.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index a0fa5de..3e96e47 100644 --- a/drivers/vhost/net.c...

...9.3Mbit/s Vm1 to External throughput is 93Mbit/s Simple performance test on 40gbe shows no obvious changes in throughput after this patch. The patch only solve this issue when unlimited sndbuf. We still need a solution for limited sndbuf. Cc: Michael S. Tsirkin <mst at redhat.com> Cc: Qin Chuanyu <qinchuanyu at huawei.com> Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/vhost/net.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index a0fa5de..3e96e47 100644 --- a/drivers/vhost/net.c...

...gt; > throughput and cpu utilization with this patch. >> > >> > The patch only solve this issue when unlimited sndbuf. We still need a >> > solution for limited sndbuf. >> > >> > Cc: Michael S. Tsirkin <mst at redhat.com> >> > Cc: Qin Chuanyu <qinchuanyu at huawei.com> >> > Signed-off-by: Jason Wang <jasowang at redhat.com> > I thought hard about this. > Here's what worries me: if there are still head of line > blocking issues lurking in the stack, they will still > hurt guests such as windows which...

...gt; > throughput and cpu utilization with this patch. >> > >> > The patch only solve this issue when unlimited sndbuf. We still need a >> > solution for limited sndbuf. >> > >> > Cc: Michael S. Tsirkin <mst at redhat.com> >> > Cc: Qin Chuanyu <qinchuanyu at huawei.com> >> > Signed-off-by: Jason Wang <jasowang at redhat.com> > I thought hard about this. > Here's what worries me: if there are still head of line > blocking issues lurking in the stack, they will still > hurt guests such as windows which...

This fixes a deadlock with vhost reported in the field, as well as a theoretical race issue found by code review. Patches 1+2 are needed for stable. Thanks to Qin Chuanyu for reporting the issue! Michael S. Tsirkin (3): kref: add kref_sub_return vhost: fix ref cnt checking deadlock vhost: fix a theoretical race in device cleanup include/linux/kref.h | 33 ++++++++++++++++++++++++++++++++- drivers/vhost/net.c | 15 ++++++++++----- 2 files changed, 42 insert...

This fixes a deadlock with vhost reported in the field, as well as a theoretical race issue found by code review. Patches 1+2 are needed for stable. Thanks to Qin Chuanyu for reporting the issue! Michael S. Tsirkin (3): kref: add kref_sub_return vhost: fix ref cnt checking deadlock vhost: fix a theoretical race in device cleanup include/linux/kref.h | 33 ++++++++++++++++++++++++++++++++- drivers/vhost/net.c | 15 ++++++++++----- 2 files changed, 42 insert...