> -----Original Message----- > From: Maxime Coquelin <maxime.coque...@redhat.com> > Sent: Thursday, September 23, 2021 4:50 PM > To: Xia, Chenbo <chenbo....@intel.com>; Eugenio Pérez <epere...@redhat.com> > Cc: dev@dpdk.org; Pei Zhang <pezh...@redhat.com>; Jason Wang > <jasow...@redhat.com> > Subject: Re: [PATCH] vhost: Clean iotlb cache on vring stop > > > > On 9/23/21 10:48, Xia, Chenbo wrote: > > Hi Maxime, > > > >> -----Original Message----- > >> From: Maxime Coquelin <maxime.coque...@redhat.com> > >> Sent: Thursday, September 23, 2021 4:34 PM > >> To: Eugenio Pérez <epere...@redhat.com>; Xia, Chenbo <chenbo....@intel.com> > >> Cc: dev@dpdk.org; Pei Zhang <pezh...@redhat.com>; Jason Wang > >> <jasow...@redhat.com> > >> Subject: Re: [PATCH] vhost: Clean iotlb cache on vring stop > >> > >> > >> > >> On 8/27/21 18:12, Eugenio Pérez wrote: > >>> Old IOVA cache entries are left when there is a change on virtio driver > >>> in VM. In case that all these old entries have iova addresses lesser > >>> than new iova entries, vhost code will need to iterate all the cache to > >>> find the new ones. In case of just a new iova entry needed for the new > >>> translations, this condition will last forever. > >>> > >>> This has been observed in virtio-net to testpmd's vfio-pci driver > >>> transition, reducing the performance from more than 10Mpps to less than > >>> 0.07Mpps if the hugepage address was higher than the networking > >>> buffers. Since all new buffers are contained in this new gigantic page, > >>> vhost needs to scan IOTLB_CACHE_SIZE - 1 for each translation at worst. > >>> > >>> Signed-off-by: Eugenio Pérez <epere...@redhat.com> > >>> Reported-by: Pei Zhang <pezh...@redhat.com> > >>> --- > >>> lib/vhost/vhost_user.c | 2 ++ > >>> 1 file changed, 2 insertions(+) > >>> > >>> diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c > >>> index 29a4c9af60..7de48f5333 100644 > >>> --- a/lib/vhost/vhost_user.c > >>> +++ b/lib/vhost/vhost_user.c > >>> @@ -2113,6 +2113,8 @@ vhost_user_get_vring_base(struct virtio_net **pdev, > >>> msg->size = sizeof(msg->payload.state); > >>> msg->fd_num = 0; > >>> > >>> + vhost_user_iotlb_flush_all(vq); > >>> + > >>> vring_invalidate(dev, vq); > >>> > >>> return RTE_VHOST_MSG_RESULT_REPLY; > >>> > >> > >> Reviewed-by: Maxime Coquelin <maxime.coque...@redhat.com> > > > > So you will fix title and add fix tag when applying, right? > > Yes, I will. Thanks for the heads-up!
Cool! With both fixed: Reviewed-by: Chenbo Xia <chenbo....@intel.com> > > Maxime > > > /Chenbo > > > >> > >> Thanks, > >> Maxime > >
