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From: "Wang, Shawn" <xingbow-vV1OtcyAfmbQT0dZR+AlfA@public.gmane.org>
To: Dmitry Vyal <dmitryvyal-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Michael Quicquaro
	<michael.quicquaro-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	"dev-VfR2kkLFssw@public.gmane.org"
	<dev-VfR2kkLFssw@public.gmane.org>
Cc: "mayhan-0C9CrKKbv28dnm+yROfE0A@public.gmane.org"
	<mayhan-0C9CrKKbv28dnm+yROfE0A@public.gmane.org>
Subject: Re: Rx-errors with testpmd (only 75% line rate)
Date: Wed, 22 Jan 2014 17:46:14 +0000	[thread overview]
Message-ID: <CF054383.45272%xingbow@amazon.com> (raw)
In-Reply-To: <52DFDB10.2090906-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

Does your NIC connect directly to your Socket?
If not, the packet might go through QPI, which will cause additional
latency.
Check your motherboard.

Wang, Shawn




On 1/22/14, 6:52 AM, "Dmitry Vyal" <dmitryvyal-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:

>Hello MIchael,
>
>I suggest you to check average burst sizes on receive queues. Looks like
>I stumbled upon a similar issue several times. If you are calling
>rte_eth_rx_burst too frequently, NIC begins losing packets no matter how
>many CPU horse power you have (more you have, more it loses, actually).
>In my case this situation occured when average burst size is less than
>20 packets or so. I'm not sure what's the reason for this behavior, but
>I observed it on several applications on Intel 82599 10Gb cards.
>
>Regards, Dmitry
>
>
>On 01/09/2014 11:28 PM, Michael Quicquaro wrote:
>> Hello,
>> My hardware is a Dell PowerEdge R820:
>> 4x Intel Xeon E5-4620 2.20GHz 8 core
>> 16GB RDIMM 1333 MHz Dual Rank, x4 - Quantity 16
>> Intel X520 DP 10Gb DA/SFP+
>>
>> So in summary 32 cores @ 2.20GHz and 256GB RAM
>>
>> ... plenty of horsepower.
>>
>> I've reserved 16 1GB Hugepages
>>
>> I am configuring only one interface and using testpmd in rx_only mode to
>> first see if I can receive at line rate.
>>
>> I am generating traffic on a different system which is running the
>>netmap
>> pkt-gen program - generating 64 byte packets at close to line rate.
>>
>> I am only able to receive approx. 75% of line rate and I see the
>>Rx-errors
>> in the port stats going up proportionally.
>> I have verified that all receive queues are being used, but strangely
>> enough, it doesn't matter how many queues more than 2 that I use, the
>> throughput is the same.  I have verified with 'mpstat -P ALL' that all
>> specified cores are used.  The utilization of each core is only roughly
>>25%.
>>
>> Here is my command line:
>> testpmd -c 0xffffffff -n 4 -- --nb-ports=1 --coremask=0xfffffffe
>> --nb-cores=8 --rxd=2048 --txd=2048 --mbcache=512 --burst=512 --rxq=8
>> --txq=8 --interactive
>>
>> What can I do to trace down this problem?  It seems very similar to a
>> thread on this list back in May titled "Best example for showing
>> throughput?" where no resolution was ever mentioned in the thread.
>>
>> Thanks for any help.
>> - Michael
>

  parent reply	other threads:[~2014-01-22 17:46 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-09 19:28 Rx-errors with testpmd (only 75% line rate) Michael Quicquaro
     [not found] ` <CAAD-K97KDoGVow6dVrKdRtCyD+wgJchO4OJFpGTRDgiaq5=Stw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-01-09 21:21   ` François-Frédéric Ozog
2014-01-22 14:52   ` Dmitry Vyal
     [not found]     ` <52DFDB10.2090906-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2014-01-22 17:46       ` Wang, Shawn [this message]
2014-01-27 20:00       ` Michael Quicquaro
     [not found]         ` <CAAD-K94NjnoFwFnTdAyEyDecm6E-WTPgzaZmAeh5bAAAap8QvQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-01-28  8:31           ` Dmitry Vyal
     [not found]             ` <52E76AD3.9040404-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2014-02-10 17:34               ` Jun Han
2014-01-22 20:38   ` Robert Sanford
     [not found]     ` <CAFmpvUNHqpp0DhsFXtYQOxDObV_K5Qs2B=w7miynMADpP21C5A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-01-23 23:22       ` Michael Quicquaro
     [not found]         ` <CAAD-K9777Tp7tptsfXm6RbAEWJMdd6juGrthAe_MHB1U1JHfDw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-01-24  9:18           ` François-Frédéric Ozog

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