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From: Kai Zhang <zhang.4522-ZbGKxL/pcrQ@public.gmane.org>
To: "dev-VfR2kkLFssw@public.gmane.org" <dev-VfR2kkLFssw@public.gmane.org>
Subject: About round trip latency with DPDK
Date: Wed, 23 Jul 2014 15:24:49 -0400	[thread overview]
Message-ID: <CACKSPmcELVBJRK0ZYyy1r7MJJCGmq4kfY5==TGKD2LLKuTDJ-A@mail.gmail.com> (raw)

Hello,

I am trying to develop a low-latency application, and I measured the round
trip latency with DPDK. However I got an average of 650~720 microseconds
round-trip latency with Intel 82599 10Gbps NIC.

The experiment method is as follows. 2 machines (A and B) are connected
back-to-back. Machine A embeds a time stamp in the packet and sends to B, B
(use testpmd or l2fwd) forwards packets back to A immediately (A->B->A),
and A receives packets and calculates time difference between current time
and the embedded time stamp. (code :
https://github.com/kay21s/dpdk/tree/master/examples/recv_send)

I have 3 machines, and performing the above experiment on each pair leads
to a similar latency. However, previous academic papers report that DPDK
offers only a few 10 microseconds round trip latency.

What's the round trip latency DPDK is supposed to offer? Have you measured
it at Intel?

Thanks a lot,
Kai

             reply	other threads:[~2014-07-23 19:24 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-23 19:24 Kai Zhang [this message]
     [not found] ` <CACKSPmcELVBJRK0ZYyy1r7MJJCGmq4kfY5==TGKD2LLKuTDJ-A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-07-24  8:36   ` About round trip latency with DPDK Alex Markuze
  -- strict thread matches above, loose matches on Subject: below --
2014-07-24 12:48 Wodkowski, PawelX
     [not found] ` <F6F2A6264E145F47A18AB6DF8E87425D12B0782C-kPTMFJFq+rFP9JyJpTNKArfspsVTdybXVpNB7YpNyf8@public.gmane.org>
2014-07-25 14:21   ` Kai Zhang

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