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From: Kai Zhang <zhang.4522@osu.edu>
To: "Richardson, Bruce" <bruce.richardson@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] Running independent processes on the same machine
Date: Sun, 20 Jul 2014 20:19:09 -0400	[thread overview]
Message-ID: <CACKSPmf1a2A4LaeL03JqiSP9oYU7bEAs8OH_khbuOBBpmpM4ig@mail.gmail.com> (raw)
In-Reply-To: <59AF69C657FD0841A61C55336867B5B0343B0A39@IRSMSX103.ger.corp.intel.com>

Hi Bruce,

Thanks for your help. I have implemented rx and tx in the same program to
measure round trip latency.

2 machines (A and B) are connected back-to-back with Intel 82599 NIC.
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 got an average of 650~720 microseconds round-trip latency. 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:[~2014-07-21  0:18 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-20 18:03 Kai Zhang
2014-07-20 19:15 ` Richardson, Bruce
2014-07-21  0:19   ` Kai Zhang [this message]

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