From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: "Wang, Zhihong" <zhihong.wang@intel.com>,
"yuanhan.liu@linux.intel.com" <yuanhan.liu@linux.intel.com>,
"Xie, Huawei" <huawei.xie@intel.com>,
"dev@dpdk.org" <dev@dpdk.org>
Cc: "vkaplans@redhat.com" <vkaplans@redhat.com>,
"mst@redhat.com" <mst@redhat.com>,
"stephen@networkplumber.org" <stephen@networkplumber.org>
Subject: Re: [dpdk-dev] [PATCH v4] vhost: Add indirect descriptors support to the TX path
Date: Mon, 17 Oct 2016 13:23:23 +0200 [thread overview]
Message-ID: <f1129452-af2e-b8ae-600c-492182bec06d@redhat.com> (raw)
In-Reply-To: <70cc3b89-d680-1519-add3-f38b228e65b5@redhat.com>
On 10/14/2016 05:50 PM, Maxime Coquelin wrote:
>
>
> On 10/14/2016 09:24 AM, Wang, Zhihong wrote:
>>
>>
>>> -----Original Message-----
>>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Maxime Coquelin
>>> Sent: Tuesday, September 27, 2016 4:43 PM
>>> To: yuanhan.liu@linux.intel.com; Xie, Huawei <huawei.xie@intel.com>;
>>> dev@dpdk.org
>>> Cc: vkaplans@redhat.com; mst@redhat.com;
>>> stephen@networkplumber.org; Maxime Coquelin
>>> <maxime.coquelin@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@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.
The root cause is identified.
When INDIRECT_DESC feature is negotiated, Windows guest uses indirect
for both Tx and Rx descriptors, whereas Linux guests (Virtio PMD &
virtio-net kernel driver) use indirect only for Tx.
I'll implement indirect support for the Rx path in vhost lib, but the
change will be too big for -rc release.
I propose in the mean time to disable INDIRECT_DESC feature in vhost
lib, we can still enable it locally for testing.
Yuanhan, is it ok for you?
> Has anyone already tested Windows guest with vhost-net, which also has
> indirect descs support?
I tested and confirm it works with vhost-net.
Regards,
Maxime
next prev parent reply other threads:[~2016-10-17 11:23 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-23 8:28 [dpdk-dev] [PATCH v3] " Maxime Coquelin
2016-09-23 15:49 ` Michael S. Tsirkin
2016-09-23 18:02 ` Maxime Coquelin
2016-09-23 18:06 ` Michael S. Tsirkin
2016-09-23 18:16 ` Maxime Coquelin
2016-09-23 18:22 ` Michael S. Tsirkin
2016-09-23 20:24 ` Stephen Hemminger
2016-09-26 3:03 ` Yuanhan Liu
2016-09-26 12:25 ` Michael S. Tsirkin
2016-09-26 13:04 ` Yuanhan Liu
2016-09-27 4:15 ` Yuanhan Liu
2016-09-27 7:25 ` Maxime Coquelin
2016-09-27 8:42 ` [dpdk-dev] [PATCH v4] " Maxime Coquelin
2016-09-27 12:18 ` Yuanhan Liu
2016-10-14 7:24 ` Wang, Zhihong
2016-10-14 7:34 ` Wang, Zhihong
2016-10-14 15:50 ` Maxime Coquelin
2016-10-17 11:23 ` Maxime Coquelin [this message]
2016-10-17 13:21 ` Yuanhan Liu
2016-10-17 14:14 ` Maxime Coquelin
2016-10-27 9:00 ` Wang, Zhihong
2016-10-27 9:10 ` Maxime Coquelin
2016-10-27 9:55 ` Maxime Coquelin
2016-10-27 10:19 ` Wang, Zhihong
2016-10-28 7:32 ` Pierre Pfister (ppfister)
2016-10-28 7:58 ` Maxime Coquelin
2016-11-01 8:15 ` Yuanhan Liu
2016-11-01 9:39 ` Thomas Monjalon
2016-11-02 2:44 ` Yuanhan Liu
2016-10-27 10:33 ` Yuanhan Liu
2016-10-27 10:35 ` Maxime Coquelin
2016-10-27 10:46 ` Yuanhan Liu
2016-10-28 0:49 ` Wang, Zhihong
2016-10-28 7:42 ` Maxime Coquelin
2016-10-31 10:01 ` Wang, Zhihong
2016-11-02 10:51 ` Maxime Coquelin
2016-11-03 8:11 ` Maxime Coquelin
2016-11-04 6:18 ` Xu, Qian Q
2016-11-04 7:41 ` Maxime Coquelin
2016-11-04 7:20 ` Wang, Zhihong
2016-11-04 7:57 ` Maxime Coquelin
2016-11-04 7:59 ` Maxime Coquelin
2016-11-04 10:43 ` Wang, Zhihong
2016-11-04 11:22 ` Maxime Coquelin
2016-11-04 11:36 ` Yuanhan Liu
2016-11-04 11:39 ` Maxime Coquelin
2016-11-04 12:30 ` Wang, Zhihong
2016-11-04 12:54 ` Maxime Coquelin
2016-11-04 13:09 ` Wang, Zhihong
2016-11-08 10:51 ` Wang, Zhihong
2016-10-27 10:53 ` Maxime Coquelin
2016-10-28 6:05 ` Xu, Qian Q
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=f1129452-af2e-b8ae-600c-492182bec06d@redhat.com \
--to=maxime.coquelin@redhat.com \
--cc=dev@dpdk.org \
--cc=huawei.xie@intel.com \
--cc=mst@redhat.com \
--cc=stephen@networkplumber.org \
--cc=vkaplans@redhat.com \
--cc=yuanhan.liu@linux.intel.com \
--cc=zhihong.wang@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).