From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH 0/6] vhost: add Tx zero copy support
Date: Tue, 23 Aug 2016 18:41:02 +0200 [thread overview]
Message-ID: <67343933-17b0-6dc9-47cf-0ee04ec1b6c3@redhat.com> (raw)
In-Reply-To: <20160823145322.GR30752@yliu-dev.sh.intel.com>
On 08/23/2016 04:53 PM, Yuanhan Liu wrote:
> BTW, I really appreicate your efforts on reviewing this patchset.
>
> It would be great if you could take some time to review my another
> patchset :)
>
> [PATCH 0/7] vhost: vhost-cuse removal and code path refactoring
>
> It touchs a large of code base, that I wish I could apply it ASAP.
> So that the chance a later patch will introduce conflicts is small.
Sure, I will try to review it by tomorrow morning (CET).
REgards,
Maxime
>
> --yliu
>
> On Tue, Aug 23, 2016 at 10:42:11PM +0800, Yuanhan Liu wrote:
>> On Tue, Aug 23, 2016 at 04:18:40PM +0200, Maxime Coquelin wrote:
>>>
>>>
>>> On 08/23/2016 10:10 AM, Yuanhan Liu wrote:
>>>> This patch set enables vhost Tx zero copy. The majority work goes to
>>>> patch 4: vhost: add Tx zero copy.
>>>>
>>>> The basic idea of Tx zero copy is, instead of copying data from the
>>>> desc buf, here we let the mbuf reference the desc buf addr directly.
>>>>
>>>> The major issue behind that is how and when to update the used ring.
>>>> You could check the commit log of patch 4 for more details.
>>>>
>>>> Patch 5 introduces a new flag, RTE_VHOST_USER_TX_ZERO_COPY, to enable
>>>> Tx zero copy, which is disabled by default.
>>>>
>>>> Few more TODOs are left, including handling a desc buf that is across
>>>> two physical pages, updating release note, etc. Those will be fixed
>>>> in later version. For now, here is a simple one that hopefully it
>>>> shows the idea clearly.
>>>>
>>>> I did some quick tests, the performance gain is quite impressive.
>>>>
>>>> For a simple dequeue workload (running rxonly in vhost-pmd and runnin
>>>> txonly in guest testpmd), it yields 40+% performance boost for packet
>>>> size 1400B.
>>>>
>>>> For VM2VM iperf test case, it's even better: about 70% boost.
>>>
>>> This is indeed impressive.
>>> Somewhere else, you mention that there is a small regression with small
>>> packets. Do you have some figures to share?
>>
>> It could be 15% drop for PVP case with 64B packet size. The test topo is:
>>
>> nic 0 --> VM Rx --> VM Tx --> nic 0
>>
>> Put simply, I run vhost-switch example in the host and run testpmd in
>> the guest.
>>
>> Though the number looks big, I don't think it's an issue. First of all,
>> it's disabled by default. Secondly, if you want to enable it, you should
>> be certain that the packet size is normally big, otherwise, you should
>> not bother to try with zero copy.
>>
>>> Also, with this feature OFF, do you see some regressions for both small
>>> and bigger packets?
>>
>> Good question. I didn't check it on purpose, but I did try when it's
>> disabled, the number I got is pretty the same as the one I got without
>> this feature. So, I would say I don't see regressions. Anyway, I could
>> do more tests to make sure.
>>
>> --yliu
next prev parent reply other threads:[~2016-08-23 16:41 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-23 8:10 Yuanhan Liu
2016-08-23 8:10 ` [dpdk-dev] [PATCH 1/6] vhost: simplify memory regions handling Yuanhan Liu
2016-08-23 9:17 ` Maxime Coquelin
2016-08-24 7:26 ` Xu, Qian Q
2016-08-24 7:40 ` Yuanhan Liu
2016-08-24 7:36 ` Xu, Qian Q
2016-08-23 8:10 ` [dpdk-dev] [PATCH 2/6] vhost: get guest/host physical address mappings Yuanhan Liu
2016-08-23 9:58 ` Maxime Coquelin
2016-08-23 12:32 ` Yuanhan Liu
2016-08-23 13:25 ` Maxime Coquelin
2016-08-23 13:49 ` Yuanhan Liu
2016-08-23 14:05 ` Maxime Coquelin
2016-08-23 8:10 ` [dpdk-dev] [PATCH 3/6] vhost: introduce last avail idx for Tx Yuanhan Liu
2016-08-23 12:27 ` Maxime Coquelin
2016-08-23 8:10 ` [dpdk-dev] [PATCH 4/6] vhost: add Tx zero copy Yuanhan Liu
2016-08-23 14:04 ` Maxime Coquelin
2016-08-23 14:31 ` Yuanhan Liu
2016-08-23 15:40 ` Maxime Coquelin
2016-08-23 8:10 ` [dpdk-dev] [PATCH 5/6] vhost: add a flag to enable " Yuanhan Liu
2016-09-06 9:00 ` Xu, Qian Q
2016-09-06 9:42 ` Xu, Qian Q
2016-09-06 10:02 ` Yuanhan Liu
2016-09-07 2:43 ` Xu, Qian Q
2016-09-06 9:55 ` Yuanhan Liu
2016-09-07 16:00 ` Thomas Monjalon
2016-09-08 7:21 ` Yuanhan Liu
2016-09-08 7:57 ` Thomas Monjalon
2016-08-23 8:10 ` [dpdk-dev] [PATCH 6/6] examples/vhost: add an option " Yuanhan Liu
2016-08-23 9:31 ` Thomas Monjalon
2016-08-23 12:33 ` Yuanhan Liu
2016-08-23 14:14 ` Maxime Coquelin
2016-08-23 14:45 ` Yuanhan Liu
2016-08-23 14:18 ` [dpdk-dev] [PATCH 0/6] vhost: add Tx zero copy support Maxime Coquelin
2016-08-23 14:42 ` Yuanhan Liu
2016-08-23 14:53 ` Yuanhan Liu
2016-08-23 16:41 ` Maxime Coquelin [this message]
2016-08-29 8:32 ` Xu, Qian Q
2016-08-29 8:57 ` Xu, Qian Q
2016-09-23 4:11 ` Yuanhan Liu
2016-10-09 15:20 ` Yuanhan Liu
2016-09-23 4:13 ` [dpdk-dev] [PATCH v2 0/7] vhost: add dequeue " Yuanhan Liu
2016-09-23 4:13 ` [dpdk-dev] [PATCH v2 1/7] vhost: simplify memory regions handling Yuanhan Liu
2016-09-23 4:13 ` [dpdk-dev] [PATCH v2 2/7] vhost: get guest/host physical address mappings Yuanhan Liu
2016-09-26 20:17 ` Maxime Coquelin
2016-09-23 4:13 ` [dpdk-dev] [PATCH v2 3/7] vhost: introduce last avail idx for dequeue Yuanhan Liu
2016-09-23 4:13 ` [dpdk-dev] [PATCH v2 4/7] vhost: add dequeue zero copy Yuanhan Liu
2016-09-26 20:45 ` Maxime Coquelin
2016-10-06 14:37 ` Xu, Qian Q
2016-10-09 2:03 ` Yuanhan Liu
2016-10-10 10:12 ` Xu, Qian Q
2016-10-10 10:14 ` Maxime Coquelin
2016-10-10 10:22 ` Xu, Qian Q
2016-10-10 10:40 ` Xu, Qian Q
2016-10-10 11:48 ` Maxime Coquelin
2016-09-23 4:13 ` [dpdk-dev] [PATCH v2 5/7] vhost: add a flag to enable " Yuanhan Liu
2016-09-26 20:57 ` Maxime Coquelin
2016-09-23 4:13 ` [dpdk-dev] [PATCH v2 6/7] examples/vhost: add an option " Yuanhan Liu
2016-09-26 21:05 ` Maxime Coquelin
2016-09-23 4:13 ` [dpdk-dev] [PATCH v2 7/7] net/vhost: " Yuanhan Liu
2016-09-26 21:05 ` Maxime Coquelin
2016-10-09 7:27 ` [dpdk-dev] [PATCH v3 0/7] vhost: add dequeue zero copy support Yuanhan Liu
2016-10-09 7:27 ` [dpdk-dev] [PATCH v3 1/7] vhost: simplify memory regions handling Yuanhan Liu
2016-10-09 7:27 ` [dpdk-dev] [PATCH v3 2/7] vhost: get guest/host physical address mappings Yuanhan Liu
2016-11-29 3:10 ` linhaifeng
2016-11-29 13:14 ` linhaifeng
2016-10-09 7:27 ` [dpdk-dev] [PATCH v3 3/7] vhost: introduce last avail idx for dequeue Yuanhan Liu
2016-10-09 7:27 ` [dpdk-dev] [PATCH v3 4/7] vhost: add dequeue zero copy Yuanhan Liu
2016-10-09 7:27 ` [dpdk-dev] [PATCH v3 5/7] vhost: add a flag to enable " Yuanhan Liu
2016-10-09 7:27 ` [dpdk-dev] [PATCH v3 6/7] examples/vhost: add an option " Yuanhan Liu
2016-10-09 7:28 ` [dpdk-dev] [PATCH v3 7/7] net/vhost: " Yuanhan Liu
2016-10-11 13:04 ` [dpdk-dev] [PATCH v3 0/7] vhost: add dequeue zero copy support Xu, Qian Q
2016-10-12 7:48 ` Yuanhan Liu
2016-10-09 10:46 ` [dpdk-dev] [PATCH 0/6] vhost: add Tx " linhaifeng
2016-10-10 8:03 ` Yuanhan Liu
2016-10-14 7:30 ` linhaifeng
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=67343933-17b0-6dc9-47cf-0ee04ec1b6c3@redhat.com \
--to=maxime.coquelin@redhat.com \
--cc=dev@dpdk.org \
--cc=yuanhan.liu@linux.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).