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From: Gokul Bargaje <gokulbargaje.182009@nitk.edu.in>
To: Ferruh Yigit <ferruh.yigit@intel.com>
Cc: dev@dpdk.org, users@dpdk.org
Subject: Re: [dpdk-dev] [dpdk-users] What is the 'unit of timestamp' assigned to mbuf packet in DPDK?
Date: Fri, 22 Nov 2019 22:30:11 +0530
Message-ID: <CAH1-=xh_ngR-2r2gt+e_66QRN4Ec7NbXoXqW2tQXf9Vx7tTi=w@mail.gmail.com> (raw)
In-Reply-To: <6a0d3205-e506-c0cb-3482-3224b875c650@intel.com>

Thank you for the clarification. But I am still unable to understand how
exactly timestamp is calculated before assigning to a timestamp field.
Could you please tell me the steps to calculate the timestamp in DPDK?

I have to implement the PIE AQM algorithm in DPDK and for that, I need to
calculate the total time spent by the packet waiting in queue (i.e. the
difference between enqueue time and dequeue time).

Thanks,
Gokul

On Fri, Nov 22, 2019 at 8:18 PM Ferruh Yigit <ferruh.yigit@intel.com> wrote:

> On 11/18/2019 2:29 PM, Gokul Bargaje wrote:
> > Hi,
> >
> > The timestamp assigned to packet at the time of enqueue (value of
> timestamp
> > field in mbuf), is it in milliseconds or microseconds or in cpu cycles?
>
> The unit is not defined [1]. 'rte_eth_read_clock()' was added [2] to help
> converting it to time when it is clock counter.
>
> [1]
> 918ae9dc775e ("mbuf: add a timestamp field")
>
> [2]
> 5e741377657c ("ethdev: add API to read device clock")
>
> >
> > How this timestamp is calculated? Is it calculated using the
> *rte_cycles.h*?
> >
>
>
>
>
>
>

  reply index

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-18 14:29 [dpdk-dev] " Gokul Bargaje
2019-11-22 14:48 ` [dpdk-dev] [dpdk-users] " Ferruh Yigit
2019-11-22 17:00   ` Gokul Bargaje [this message]
2019-11-22 17:05     ` Stephen Hemminger
2019-11-27 14:49     ` Tom Barbette
2019-11-28  8:28     ` Harman Kalra
2019-11-25 10:56 ` Archit Pandey

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