similar to: [PATCH net] vhost: net: switch to use data copy if pending DMAs exceed the limit

We used to stop the handling of tx when the number of pending DMAs exceeds VHOST_MAX_PEND. This is used to reduce the memory occupation of both host and guest. But it was too aggressive in some cases, since any delay or blocking of a single packet may delay or block the guest transmission. Consider the following setup: +-----+ +-----+ | VM1 | | VM2 | +--+--+

We used to stop the handling of tx when the number of pending DMAs exceeds VHOST_MAX_PEND. This is used to reduce the memory occupation of both host and guest. But it was too aggressive in some cases, since any delay or blocking of a single packet may delay or block the guest transmission. Consider the following setup: +-----+ +-----+ | VM1 | | VM2 | +--+--+

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_MAX_PEND. This is used to reduce the memory occupation >> of both host and guest. But it was too aggressive in some cases, since >> any delay or blocking of a single packet

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_MAX_PEND. This is used to reduce the memory occupation >> of both host and guest. But it was too aggressive in some cases, since >> any delay or blocking of a single packet

On Fri, Aug 30, 2013 at 12:29:22PM +0800, Jason Wang wrote: > As Michael point out, We used to limit the max pending DMAs to get better cache > utilization. But it was not done correctly since it was one done when there's no > new buffers submitted from guest. Guest can easily exceeds the limitation by > keeping sending packets. > > So this patch moves the check into main

On Fri, Aug 30, 2013 at 12:29:22PM +0800, Jason Wang wrote: > As Michael point out, We used to limit the max pending DMAs to get better cache > utilization. But it was not done correctly since it was one done when there's no > new buffers submitted from guest. Guest can easily exceeds the limitation by > keeping sending packets. > > So this patch moves the check into main

On Fri, Aug 16, 2013 at 01:16:30PM +0800, Jason Wang wrote: > We used to limit the max pending DMAs to prevent guest from pinning too many > pages. But this could be removed since: > > - We have the sk_wmem_alloc check in both tun/macvtap to do the same work > - This max pending check were almost useless since it was one done when there's > no new buffers coming from

On Fri, Aug 16, 2013 at 01:16:30PM +0800, Jason Wang wrote: > We used to limit the max pending DMAs to prevent guest from pinning too many > pages. But this could be removed since: > > - We have the sk_wmem_alloc check in both tun/macvtap to do the same work > - This max pending check were almost useless since it was one done when there's > no new buffers coming from

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_MAX_PEND. This is used to reduce the memory occupation

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_MAX_PEND. This is used to reduce the memory occupation

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

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

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_MAX_PEND. This is used to reduce the memory occupation > of both host and guest. But it was too aggressive in some cases, since > any delay or blocking of a single packet may delay or block the guest > transmission. Consider the following

On 03/10/2014 04:03 PM, Michael S. Tsirkin wrote: > On Fri, Mar 07, 2014 at 01:28:27PM +0800, Jason Wang wrote: >> > We used to stop the handling of tx when the number of pending DMAs >> > exceeds VHOST_MAX_PEND. This is used to reduce the memory occupation >> > of both host and guest. But it was too aggressive in some cases, since >> > any delay or blocking

On 03/10/2014 04:03 PM, Michael S. Tsirkin wrote: > On Fri, Mar 07, 2014 at 01:28:27PM +0800, Jason Wang wrote: >> > We used to stop the handling of tx when the number of pending DMAs >> > exceeds VHOST_MAX_PEND. This is used to reduce the memory occupation >> > of both host and guest. But it was too aggressive in some cases, since >> > any delay or blocking

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_MAX_PEND. This is used to reduce the memory occupation >>> of both host and guest. But it was too aggressive in some

Hi all: This series tries to unify and simplify vhost codes especially for zerocopy. Plase review. Thanks Jason Wang (6): vhost_net: make vhost_zerocopy_signal_used() returns void vhost_net: use vhost_add_used_and_signal_n() in vhost_zerocopy_signal_used() vhost: switch to use vhost_add_used_n() vhost_net: determine whether or not to use zerocopy at one time vhost_net: poll vhost

Hi all: This series tries to unify and simplify vhost codes especially for zerocopy. Plase review. Thanks Jason Wang (6): vhost_net: make vhost_zerocopy_signal_used() returns void vhost_net: use vhost_add_used_and_signal_n() in vhost_zerocopy_signal_used() vhost: switch to use vhost_add_used_n() vhost_net: determine whether or not to use zerocopy at one time vhost_net: poll vhost

Hi all: This series tries to unify and simplify vhost codes especially for zerocopy. With this series, 5% - 10% improvement for per cpu throughput were seen during netperf guest sending test. Plase review. Changes from V1: - Fix the zerocopy enabling check by changing the check of upend_idx != done_idx to (upend_idx + 1) % UIO_MAXIOV == done_idx. - Switch to use put_user() in

Hi all: This series tries to unify and simplify vhost codes especially for zerocopy. With this series, 5% - 10% improvement for per cpu throughput were seen during netperf guest sending test. Plase review. Changes from V1: - Fix the zerocopy enabling check by changing the check of upend_idx != done_idx to (upend_idx + 1) % UIO_MAXIOV == done_idx. - Switch to use put_user() in