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<mailto: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<http://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
>