From: Dmitry Vyal <dmitryvyal@gmail.com>
To: Michael Quicquaro <michael.quicquaro@gmail.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] Rx-errors with testpmd (only 75% line rate)
Date: Tue, 28 Jan 2014 12:31:15 +0400 [thread overview]
Message-ID: <52E76AD3.9040404@gmail.com> (raw)
In-Reply-To: <CAAD-K94NjnoFwFnTdAyEyDecm6E-WTPgzaZmAeh5bAAAap8QvQ@mail.gmail.com>
On 01/28/2014 12:00 AM, Michael Quicquaro wrote:
> Dmitry,
> I cannot thank you enough for this information. This too was my main
> problem. I put a "small" unmeasured delay before the call to
> rte_eth_rx_burst() and suddenly it starts returning bursts of 512
> packets vs. 4!!
> Best Regards,
> Mike
>
Thanks for confirming my guesses! By the way, make sure the number of
packets you receive in a single burst is less than configured queue
size. Or you will lose packets too. Maybe your "small" delay in not so
small :) For my own purposes I use a delay of about 150usecs.
P.S. I wonder why this issue is not mentioned in documentation. Is it
evident for everyone doing network programming?
>
> On Wed, Jan 22, 2014 at 9:52 AM, Dmitry Vyal <dmitryvyal@gmail.com
> <mailto:dmitryvyal@gmail.com>> 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
>
>
>
next prev parent reply other threads:[~2014-01-28 8:29 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-09 19:28 Michael Quicquaro
2014-01-09 21:21 ` François-Frédéric Ozog
2014-01-22 14:52 ` Dmitry Vyal
2014-01-22 17:46 ` Wang, Shawn
2014-01-27 20:00 ` Michael Quicquaro
2014-01-28 8:31 ` Dmitry Vyal [this message]
2014-02-10 17:34 ` Jun Han
2014-01-22 20:38 ` Robert Sanford
2014-01-23 23:22 ` Michael Quicquaro
2014-01-24 9:18 ` François-Frédéric Ozog
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