Re: Fwd: QOS sample example.

[satish amara <satishkamara@gmail.com>]

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Jasvinder,
   I have a few more questions.
Can you provide  some clarity on
tc_credits_per_periodtc_period is for how often the credits for traffic
need to be updated. Is tc_credits_per_period is fixed based on tc_rate.

Regards,
Satish Amara

On Fri, Apr 1, 2022 at 9:34 AM satish amara <satishkamara@gmail.com> wrote:

> Thanks for the info Jasvinder. I see there is an internal timer to see
> when to refill the token buckets and credits.  I have read the QOS
> document.  My understanding is that the DPDK code is using the same HQOS
> thread CPU context to implement timer functionality during the pipe
> selection and not leveraging on Linux timers or other timers.
>
> Regards,
> Satish Amara
>
> On Fri, Apr 1, 2022 at 4:36 AM Singh, Jasvinder <jasvinder.singh@intel.com>
> wrote:
>
>> Hi Satish,
>>
>>
>>
>> DPDK HQoS scheduler has internal timer to compute the credits. The time
>> difference between the two consecutive visit to the same pipe is used to
>> compute the number of tb_periods elapsed and based on that, the available
>> credits in the token bucket is computed. Each pipe has its own context
>> which stores the timestamp of the last visit  and it is used when pipe is
>> visited to schedule the packets from its queues.
>>
>>
>>
>> Thanks,
>>
>> Jasvinder
>>
>>
>>
>>
>>
>>
>>
>> *From:* satish amara <satishkamara@gmail.com>
>> *Sent:* Thursday, March 31, 2022 9:27 PM
>> *To:* Thomas Monjalon <thomas@monjalon.net>
>> *Cc:* users@dpdk.org; Singh, Jasvinder <jasvinder.singh@intel.com>;
>> Dumitrescu, Cristian <cristian.dumitrescu@intel.com>
>> *Subject:* Re: Fwd: QOS sample example.
>>
>>
>>
>> Thanks, Thomas for forwarding this to the group.
>>
>> I have one more question. Does DPDK QOS  uses any internal threads/timers
>> for the token bucket implementation?. The token
>>
>>  buckets can be implemented in different ways.  When are the tokens are
>> filled, I see there is tb_period?
>>
>> It looks like the tokens are filled when the HQOS thread is trying to
>> find the next active pipe?
>>
>>
>>
>> Regards,
>>
>> Satish Amara
>>
>>
>>
>>
>>
>>
>>
>> On Thu, Mar 31, 2022 at 3:39 PM Thomas Monjalon <thomas@monjalon.net>
>> wrote:
>>
>> +Cc QoS scheduler maintainers (see file MAINTAINERS)
>>
>> 31/03/2022 18:59, satish amara:
>> > Hi,
>> >     I am trying to understand the QOS sample scheduler application code.
>> > Trying to understand what is tc_period in the config.
>> > 30. QoS Scheduler Sample Application — Data Plane Development Kit
>> 21.05.0
>> > documentation (dpdk.org)
>> > <https://doc.dpdk.org/guides-21.05/sample_app_ug/qos_scheduler.html> Is
>> > tc_period same as  tb_period
>> > tb_period Bytes Time period that should elapse since the last credit
>> update
>> > in order for the bucket to be awarded tb_credits_per_period worth or
>> > credits.
>> > Regards,
>> > Satish Amara
>> >
>>
>>
>>
>>
>>

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