Re: [dpdk-dev] generic load balancing

[Prashant Upadhyaya <prashant.upadhyaya@aricent.com>]

Hi Stepher,

The awfulness depends upon the 'usecase'
I have eg. a usecase where I want this roundrobin behaviour.

I just want the NIC to give me a facility to use this.

Regards
-Prashant


-----Original Message-----
From: Stephen Hemminger [mailto:stephen@networkplumber.org]
Sent: Thursday, December 05, 2013 10:25 AM
To: Prashant Upadhyaya
Cc: François-Frédéric Ozog; Michael Quicquaro; dev@dpdk.org
Subject: Re: [dpdk-dev] generic load balancing

Round robin would actually be awful for any protocol because it would cause out of order packets.
That is why flow based algorithms like flow director and RSS work much better.

On Wed, Dec 4, 2013 at 8:31 PM, Prashant Upadhyaya <prashant.upadhyaya@aricent.com> wrote:
> Hi,
>
> It's a real pity that Intel 82599 NIC (and possibly others) don't have a simple round robin scheduling of packets on the configured queues.
>
> I have requested Intel earlier, and using this forum requesting again -- please please put this facility in the NIC that if I drop N queues there and configure  the NIC for some round robin scheduling on queues, then NIC should simply put the received packets one by one on queue 1, then on queue2,....,then on queueN, and then back on queue 1.
> The above is very useful in lot of load balancing cases.
>
> Regards
> -Prashant
>
>
> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of François-Frédéric
> Ozog
> Sent: Thursday, December 05, 2013 2:35 AM
> To: 'Michael Quicquaro'
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] generic load balancing
>
> Hi,
>
> As far as I can tell, this is really hardware dependent. Some hash functions allow uplink and downlink packets of the same "session" to go to the same queue (I know Chelsio can do this).
>
> For the Intel card, you may find what you want in:
> http://www.intel.com/content/www/us/en/ethernet-controllers/82599-10-g
> be-con
> troller-datasheet.html
>
> Other cards require NDA or other agreements to get details of RSS.
>
> If you have a performance problem, may I suggest you use kernel 3.10 then monitor system activity with "perf" command. For instance you can start with "perf top -a" this will give you nice information. Then your creativity will do the rest ;-) You may be surprised what comes on the top hot points...
> (the most unexpected hot function I found here was Linux syscall
> gettimeofday!!!)
>
> François-Frédéric
>
>> -----Message d'origine-----
>> De : dev [mailto:dev-bounces@dpdk.org] De la part de Michael
>> Quicquaro Envoyé : mercredi 4 décembre 2013 18:53 À : dev@dpdk.org Objet :
>> [dpdk-dev] generic load balancing
>>
>> Hi all,
>> I am writing a dpdk application that will receive packets from one
>> interface and process them.  It does not forward packets in the
> traditional
>> sense.  However, I do need to process them at full line rate and
>> therefore need more than one core.  The packets can be somewhat
>> generic in nature
> and
>> can be nearly identical (especially at the beginning of the packet).
>> I've used the rxonly function of testpmd as a model.
>>
>> I've run into problems in processing a full line rate of data since
>> the nature of the data causes all the data to be presented to only one core.
> I
>> get a large percentage of dropped packets (shows up as Rx-Errors in
>> "port
>> stats") because of this.  I've tried modifying the data so that
>> packets have different UDP ports and that seems to work when I use
>> --rss-udp
>>
>> My questions are:
>> 1) Is there a way to configure RSS so that it alternates packets to
>> all configured cores regardless of the packet data?
>>
>> 2)  Where is the best place to learn more about RSS and how to
>> configure it? I have not found much in the DPDK documentation.
>>
>> Thanks for the help,
>> - Mike
>
>
>
>
>
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