On 10/14/2016 09:24 AM, Wang, Zhihong wrote: > > >> -----Original Message----- >> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Maxime Coquelin >> Sent: Tuesday, September 27, 2016 4:43 PM >> To: yuanhan.liu at linux.intel.com; Xie, Huawei <huawei.xie at intel.com>; >> dev at dpdk.org >> Cc: vkaplans at redhat.com; mst at redhat.com; >> stephen at networkplumber.org; Maxime Coquelin >> <maxime.coquelin at redhat.com> >> Subject: [dpdk-dev] [PATCH v4] vhost: Add indirect descriptors support to >> the TX path >> >> Indirect descriptors are usually supported by virtio-net devices, >> allowing to dispatch a larger number of requests. >> >> When the virtio device sends a packet using indirect descriptors, >> only one slot is used in the ring, even for large packets. >> >> The main effect is to improve the 0% packet loss benchmark. >> A PVP benchmark using Moongen (64 bytes) on the TE, and testpmd >> (fwd io for host, macswap for VM) on DUT shows a +50% gain for >> zero loss. >> >> On the downside, micro-benchmark using testpmd txonly in VM and >> rxonly on host shows a loss between 1 and 4%.i But depending on >> the needs, feature can be disabled at VM boot time by passing >> indirect_desc=off argument to vhost-user device in Qemu. >> >> Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com> > > > Hi Maxime, > > Seems this patch can't with Windows virtio guest in my test. > Have you done similar tests before? > > The way I test: > > 1. Make sure https://patchwork.codeaurora.org/patch/84339/ is applied > > 2. Start testpmd with iofwd between 2 vhost ports > > 3. Start 2 Windows guests connected to the 2 vhost ports > > 4. Disable firewall and assign IP to each guest using ipconfig > > 5. Use ping to test connectivity > > When I disable this patch by setting: > > 0ULL << VIRTIO_RING_F_INDIRECT_DESC, > > the connection is fine, but when I restore: > > 1ULL << VIRTIO_RING_F_INDIRECT_DESC, > > the connection is broken.
Just noticed I didn't reply to all this morning. I sent a debug patch to Zhihong, which shows that indirect desc chaining looks OK. On my side, I just setup 2 Windows 2016 VMs, and confirm the issue. I'll continue the investigation early next week. Has anyone already tested Windows guest with vhost-net, which also has indirect descs support? Regards, Maxime