similar to: [PATCHv3 0/4] qemu-kvm: vhost net support

What it is: vhost net is a character device that can be used to reduce the number of system calls involved in virtio networking. Existing virtio net code is used in the guest without modification. There's similarity with vringfd, with some differences and reduced scope - uses eventfd for signalling - structures can be moved around in memory at any time (good for migration) - support memory

What it is: vhost net is a character device that can be used to reduce the number of system calls involved in virtio networking. Existing virtio net code is used in the guest without modification. There's similarity with vringfd, with some differences and reduced scope - uses eventfd for signalling - structures can be moved around in memory at any time (good for migration) - support memory

This adds support for vhost-net virtio kernel backend. To enable (assuming device eth2): 1. enable promisc mode or program guest mac in device eth2 2. disable tso, gso, lro, jumbo frames on the card (disabling lro + jumbo frames should be sufficient, haven't tested this) 3. add vhost=eth2 to -net flag 4. run with CAP_NET_ADMIN priviledge (e.g. root) This patch is RFC, but works without

This adds support for vhost-net virtio kernel backend. To enable (assuming device eth2): 1. enable promisc mode or program guest mac in device eth2 2. disable tso, gso, lro, jumbo frames on the card (disabling lro + jumbo frames should be sufficient, haven't tested this) 3. add vhost=eth2 to -net flag 4. run with CAP_NET_ADMIN priviledge (e.g. root) This patch is RFC, but works without

On Thu, Oct 22, 2015 at 01:27:29AM -0400, Jason Wang wrote: > This patch tries to poll for new added tx buffer for a while at the > end of tx processing. The maximum time spent on polling were limited > through a module parameter. To avoid block rx, the loop will end it > there's new other works queued on vhost so in fact socket receive > queue is also be polled. > >

On Thu, Oct 22, 2015 at 01:27:29AM -0400, Jason Wang wrote: > This patch tries to poll for new added tx buffer for a while at the > end of tx processing. The maximum time spent on polling were limited > through a module parameter. To avoid block rx, the loop will end it > there's new other works queued on vhost so in fact socket receive > queue is also be polled. > >

This adds support for vhost-net virtio kernel backend. This is not intented for merge. See vhost net patch description for details. This applies on top of commit 47e465f031fc43c53ea8f08fa55cc3482c6435c8 in Avi's tree. It won't apply to tree tip. TODO: rebase. The patchset also includes raw socket backend since I find it useful for testing vhost. When we get to merging, there's no

This adds support for vhost-net virtio kernel backend. This is not intented for merge. See vhost net patch description for details. This applies on top of commit 47e465f031fc43c53ea8f08fa55cc3482c6435c8 in Avi's tree. It won't apply to tree tip. TODO: rebase. The patchset also includes raw socket backend since I find it useful for testing vhost. When we get to merging, there's no

This still causes corruption issues for people so don't try to use in production please. Posting to expedite debugging. This adds infrastructure required for supporting multiple ring formats. The idea is as follows: we convert descriptors to an independent format first, and process that converting to iov later. Used ring is similar: we fetch into an independent struct first, convert that to

This still causes corruption issues for people so don't try to use in production please. Posting to expedite debugging. This adds infrastructure required for supporting multiple ring formats. The idea is as follows: we convert descriptors to an independent format first, and process that converting to iov later. Used ring is similar: we fetch into an independent struct first, convert that to

On Fri, Aug 16, 2013 at 01:16:26PM +0800, Jason Wang wrote: > Switch to use vhost_add_used_and_signal_n() to avoid multiple calls to > vhost_add_used_and_signal(). With the patch we will call at most 2 times > (consider done_idx warp around) compared to N times w/o this patch. > > Signed-off-by: Jason Wang <jasowang at redhat.com> So? Does this help performance then? >

On Fri, Aug 16, 2013 at 01:16:26PM +0800, Jason Wang wrote: > Switch to use vhost_add_used_and_signal_n() to avoid multiple calls to > vhost_add_used_and_signal(). With the patch we will call at most 2 times > (consider done_idx warp around) compared to N times w/o this patch. > > Signed-off-by: Jason Wang <jasowang at redhat.com> So? Does this help performance then? >

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

This adds support for vhost-net virtio kernel backend. This patch is not intended to being merged yet. I'm posting it for the benefit of people testing the backend. Usage instructions: vhost currently requires MSI-X support in guest virtio. This means guests kernel version should be >= 2.6.31. To enable vhost, simply add ",vhost" flag to nic options. Example with tap backend:

This adds support for vhost-net virtio kernel backend. This patch is not intended to being merged yet. I'm posting it for the benefit of people testing the backend. Usage instructions: vhost currently requires MSI-X support in guest virtio. This means guests kernel version should be >= 2.6.31. To enable vhost, simply add ",vhost" flag to nic options. Example with tap backend:

On 08/20/2013 10:33 AM, Jason Wang wrote: > On 08/16/2013 05:54 PM, Michael S. Tsirkin wrote: >> On Fri, Aug 16, 2013 at 01:16:26PM +0800, Jason Wang wrote: >>>> Switch to use vhost_add_used_and_signal_n() to avoid multiple calls to >>>> vhost_add_used_and_signal(). With the patch we will call at most 2 times >>>> (consider done_idx warp around)

On 08/20/2013 10:33 AM, Jason Wang wrote: > On 08/16/2013 05:54 PM, Michael S. Tsirkin wrote: >> On Fri, Aug 16, 2013 at 01:16:26PM +0800, Jason Wang wrote: >>>> Switch to use vhost_add_used_and_signal_n() to avoid multiple calls to >>>> vhost_add_used_and_signal(). With the patch we will call at most 2 times >>>> (consider done_idx warp around)

This implements vhost: a kernel-level backend for virtio, The main motivation for this work is to reduce virtualization overhead for virtio by removing system calls on data path, without guest changes. For virtio-net, this removes up to 4 system calls per packet: vm exit for kick, reentry for kick, iothread wakeup for packet, interrupt injection for packet. Some more detailed description attached

This implements vhost: a kernel-level backend for virtio, The main motivation for this work is to reduce virtualization overhead for virtio by removing system calls on data path, without guest changes. For virtio-net, this removes up to 4 system calls per packet: vm exit for kick, reentry for kick, iothread wakeup for packet, interrupt injection for packet. Some more detailed description attached