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* Re: [dpdk-dev] About round trip latency with DPDK
@ 2014-07-24 12:48 Wodkowski, PawelX
  2014-07-25 14:21 ` Kai Zhang
  0 siblings, 1 reply; 4+ messages in thread
From: Wodkowski, PawelX @ 2014-07-24 12:48 UTC (permalink / raw)
  To: dev

Refer to DPDK getting started guide paragraph 5.4. It might help.
Also it might be easier to do write simple application that send a packet on port 1 and rx it on port 2 in separate threads on separate cores (simple physical loop). You can then add timestamp and send packet back and see how long it will take TX to RX and RX to TX process.

Pawel Wodkowski
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^ permalink raw reply	[flat|nested] 4+ messages in thread
* [dpdk-dev] About round trip latency with DPDK
@ 2014-07-23 19:24 Kai Zhang
  2014-07-24  8:36 ` Alex Markuze
  0 siblings, 1 reply; 4+ messages in thread
From: Kai Zhang @ 2014-07-23 19:24 UTC (permalink / raw)
  To: dev

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

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2014-07-25 14:19 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2014-07-24 12:48 [dpdk-dev] About round trip latency with DPDK Wodkowski, PawelX
2014-07-25 14:21 ` Kai Zhang
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2014-07-23 19:24 Kai Zhang
2014-07-24  8:36 ` Alex Markuze

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