From: Michael Sardo <mike@bandex.io>
To: "Dumitrescu, Cristian" <cristian.dumitrescu@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] 4 Traffic classes per Pipe limitation
Date: Sat, 6 Jun 2015 19:23:30 -0400 [thread overview]
Message-ID: <CANG-2DLoM2U2d1L=W96pjskrNfz7owRH3OTD0GBbDjPqdWOoBA@mail.gmail.com> (raw)
In-Reply-To: <CANG-2DJoQ_4kEaKsV8M905X691gWHJcvGB+nF+t60TxmPCskmA@mail.gmail.com>
Oops, I should have searched a bit more before asking. I see that they've
already been made available:
http://dpdk.org/ml/archives/dev/attachments/20150423/17a4d8de/attachment-0001.pdf
Thanks.
-Mike
On Sat, Jun 6, 2015 at 5:05 PM, Michael Sardo <mike@bandex.io> wrote:
> Hello Cristian,
>
> Are the slides shown in that video available? They're very helpful.
>
> -Mike
>
> On Fri, Jun 5, 2015 at 4:50 PM, Dumitrescu, Cristian <
> cristian.dumitrescu@intel.com> wrote:
>
>> Hi Avinash,
>>
>> > -----Original Message-----
>> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Yeddula, Avinash
>> > Sent: Friday, June 5, 2015 6:06 PM
>> > To: dev@dpdk.org
>> > Subject: [dpdk-dev] 4 Traffic classes per Pipe limitation
>> >
>> > Hi,
>> > This is related to the QOS scheduler functionality provided by dpdk.
>> >
>> > I see a limit on the number of traffic classes to be 4. I'm exploring
>> the
>> > available options to increase that limit to 8.
>>
>> Yes, there are 4x traffic classes (scheduled in strict priority), but
>> each traffic class has 4x queues (scheduled using WFQ); for big weight
>> ratios between queues (e.g. 1:4 or 1:8, etc), WFQ becomes very similar to
>> strict priority, a king of strict priority without starvation. So the 16x
>> queues per pipe can be considered 16x sub-traffic-classes.
>>
>> You might want to watch this video on DPDK QoS:
>> https://youtu.be/_PPklkWGugs
>>
>> >
>> > This is what I found when I researched on this topic.
>> > The limitation on number's of TC (and pipes) comes from the number of
>> > bits available. Since the QoS code overloads the 32 bit RSS field in
>> > the mbuf there isn't enough bits to a lot. But then again if you add
>> lots
>> > of pipes or subports the memory footprint gets huge.
>>
>> It is not that simple. The number of 4x traffic classes in deeply built
>> into the implementation for performance reasons. Increasing the number of
>> bits allocated to traffic class in mbuf->sched would not help.
>>
>> >
>> > Any more info or suggestions on increasing the limit to 8 ?
>>
>> Yes, look at the 16x pipe queues as 16x (sub)traffic classes.
>> >
>> > Thanks
>> > -Avinash
>>
>
>
next prev parent reply other threads:[~2015-06-06 23:23 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-05 17:06 Yeddula, Avinash
2015-06-05 20:50 ` Dumitrescu, Cristian
2015-06-06 21:05 ` Michael Sardo
2015-06-06 23:23 ` Michael Sardo [this message]
2015-06-06 23:39 ` Dumitrescu, Cristian
-- strict thread matches above, loose matches on Subject: below --
2013-11-28 20:52 Ariel Rodriguez
2013-11-29 18:45 ` Dumitrescu, Cristian
2013-11-29 19:50 ` Ariel Rodriguez
2013-11-29 21:26 ` Stephen Hemminger
2013-11-29 22:33 ` Ariel Rodriguez
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