similar to: [PATCHv9] vhost: experimental tx zero-copy support

This adds experimental zero copy support in vhost-net, disabled by default. To enable, set the zerocopytx module option to 1. This patch maintains the outstanding userspace buffers in the sequence it is delivered to vhost. The outstanding userspace buffers will be marked as done once the lower device buffers DMA has finished. This is monitored through last reference of kfree_skb callback. Two

This adds experimental zero copy support in vhost-net, disabled by default. To enable, set the zerocopytx module option to 1. This patch maintains the outstanding userspace buffers in the sequence it is delivered to vhost. The outstanding userspace buffers will be marked as done once the lower device buffers DMA has finished. This is monitored through last reference of kfree_skb callback. Two

On top of 'vhost: Allow device specific fields per vq', we can move device specific fields to device virt queue from vhost virt queue. Signed-off-by: Asias He <asias at redhat.com> --- drivers/vhost/net.c | 164 +++++++++++++++++++++++++++++++++++++++++++------- drivers/vhost/vhost.c | 57 +----------------- drivers/vhost/vhost.h | 22 ------- 3 files changed, 142

On top of 'vhost: Allow device specific fields per vq', we can move device specific fields to device virt queue from vhost virt queue. Signed-off-by: Asias He <asias at redhat.com> --- drivers/vhost/net.c | 164 +++++++++++++++++++++++++++++++++++++++++++------- drivers/vhost/vhost.c | 57 +----------------- drivers/vhost/vhost.h | 22 ------- 3 files changed, 142

>From: Shirley Ma <mashirle at us.ibm.com> This adds experimental zero copy support in vhost-net, disabled by default. To enable, set experimental_zcopytx module option to 1. This patch maintains the outstanding userspace buffers in the sequence it is delivered to vhost. The outstanding userspace buffers will be marked as done once the lower device buffers DMA has finished. This is

>From: Shirley Ma <mashirle at us.ibm.com> This adds experimental zero copy support in vhost-net, disabled by default. To enable, set experimental_zcopytx module option to 1. This patch maintains the outstanding userspace buffers in the sequence it is delivered to vhost. The outstanding userspace buffers will be marked as done once the lower device buffers DMA has finished. This is

tun supports zero copy transmit since 0690899b4d4501b3505be069b9a687e68ccbe15b, however you can only enable this mode if you know your workload does not trigger heavy guest to host/host to guest traffic - otherwise you get a (minor) performance regression. This patchset addresses this problem by notifying the owner device when callback is invoked because of a data copy. This makes it possible to

tun supports zero copy transmit since 0690899b4d4501b3505be069b9a687e68ccbe15b, however you can only enable this mode if you know your workload does not trigger heavy guest to host/host to guest traffic - otherwise you get a (minor) performance regression. This patchset addresses this problem by notifying the owner device when callback is invoked because of a data copy. This makes it possible to

tun supports zero copy transmit since 0690899b4d4501b3505be069b9a687e68ccbe15b, however you can only enable this mode if you know your workload does not trigger heavy guest to host/host to guest traffic - otherwise you get a (minor) performance regression. This patchset addresses this problem by notifying the owner device when callback is invoked because of a data copy. This makes it possible to

tun supports zero copy transmit since 0690899b4d4501b3505be069b9a687e68ccbe15b, however you can only enable this mode if you know your workload does not trigger heavy guest to host/host to guest traffic - otherwise you get a (minor) performance regression. This patchset addresses this problem by notifying the owner device when callback is invoked because of a data copy. This makes it possible to

tun supports zero copy transmit since 0690899b4d4501b3505be069b9a687e68ccbe15b, however you can only enable this mode if you know your workload does not trigger heavy guest to host/host to guest traffic - otherwise you get a (minor) performance regression. This patchset addresses this problem by notifying the owner device when callback is invoked because of a data copy. This makes it possible to

tun supports zero copy transmit since 0690899b4d4501b3505be069b9a687e68ccbe15b, however you can only enable this mode if you know your workload does not trigger heavy guest to host/host to guest traffic - otherwise you get a (minor) performance regression. This patchset addresses this problem by notifying the owner device when callback is invoked because of a data copy. This makes it possible to

On Mon, Sep 02, 2013 at 04:40:59PM +0800, Jason Wang wrote: > Currently, even if the packet length is smaller than VHOST_GOODCOPY_LEN, if > upend_idx != done_idx we still set zcopy_used to true and rollback this choice > later. This could be avoided by determining zerocopy once by checking all > conditions at one time before. > > Signed-off-by: Jason Wang <jasowang at

On Mon, Sep 02, 2013 at 04:40:59PM +0800, Jason Wang wrote: > Currently, even if the packet length is smaller than VHOST_GOODCOPY_LEN, if > upend_idx != done_idx we still set zcopy_used to true and rollback this choice > later. This could be avoided by determining zerocopy once by checking all > conditions at one time before. > > Signed-off-by: Jason Wang <jasowang at

MST, This is on top of [PATCH 0/2] vhost-net fix ubuf. Asias He (11): vhost: Remove vhost_enable_zcopy in vhost.h vhost: Move VHOST_NET_FEATURES to net.c vhost: Make vhost a separate module vhost: Remove comments for hdr in vhost.h vhost: Simplify dev->vqs[i] access vhost-net: Cleanup vhost_ubuf and vhost_zcopy vhost-scsi: Remove unnecessary forward struct vhost_scsi declaration

MST, This is on top of [PATCH 0/2] vhost-net fix ubuf. Asias He (11): vhost: Remove vhost_enable_zcopy in vhost.h vhost: Move VHOST_NET_FEATURES to net.c vhost: Make vhost a separate module vhost: Remove comments for hdr in vhost.h vhost: Simplify dev->vqs[i] access vhost-net: Cleanup vhost_ubuf and vhost_zcopy vhost-scsi: Remove unnecessary forward struct vhost_scsi declaration

vhost_net_ubuf_put_and_wait has a confusing name: it will actually also free it's argument. Thus since commit 1280c27f8e29acf4af2da914e80ec27c3dbd5c01 vhost_net_flush tries to use the argument after passing it to vhost_net_ubuf_put_and_wait, this results in use after free. To fix, don't free the argument in vhost_net_ubuf_put_and_wait, add an new API for callers that want to free ubufs.

vhost_net_ubuf_put_and_wait has a confusing name: it will actually also free it's argument. Thus since commit 1280c27f8e29acf4af2da914e80ec27c3dbd5c01 vhost_net_flush tries to use the argument after passing it to vhost_net_ubuf_put_and_wait, this results in use after free. To fix, don't free the argument in vhost_net_ubuf_put_and_wait, add an new API for callers that want to free ubufs.

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 V2: - Typo fixes and code style fix - Add performance gain in the commit log of patch 2/6 - Retest the update the result in patch 6/6 Changes from V1: - Fix the zerocopy enabling check

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 V2: - Typo fixes and code style fix - Add performance gain in the commit log of patch 2/6 - Retest the update the result in patch 6/6 Changes from V1: - Fix the zerocopy enabling check