Re: [Intel-wired-lan] [PATCH next-queue v1 0/3] igc: Add support for multiple TX tstamp requests

[Vinicius Costa Gomes <vinicius.gomes@intel.com>]

Hi,

Miroslav Lichvar <mlichvar@redhat.com> writes:

> On Thu, Mar 09, 2023 at 02:57:28PM -0800, Vinicius Costa Gomes wrote:
>> Vladimir Oltean <vladimir.oltean@nxp.com> writes:
>> > If the application never generates multiple requests in flight, then
>> > this evaluation is only testing patch 3 (and patches 1 and 2 only to the
>> > extent that they don't cause a regression), right?
>> >
>> 
>> That's right. I was more interested in not causing a regression. I could
>> run the same test with two (or more) applications and give some numbers,
>> but those numbers couldn't be directly compared with the current version
>> of the code.
>> 
>> But good idea. I will change the application to send "batches" of
>> packets, so I can configure the number of "in flight" requests.
>
> If you wanted to see the impact on performance and accuracy of
> timestamps at the same time, you could use chrony as an NTP server and
> generate load with ntpperf. The server can be started as
>
> # chronyd -d local allow 'hwtimestamp eth0' 'clientloglimit 10000000'
>
> ntpperf needs to be started with the -I -H -o options to measure
> the difference between server HW TX timestamp and client HW RX
> timestamp. The PHC used by ntpperf needs to be synchronized, ideally
> via a separate PHC (e.g. by ptp4l+phc2sys).
>
> If the multi-timestamp patches work well, I'd expect the stddev
> reported by ntpperf to stay low at a higher rate. See
> https://github.com/mlichvar/ntpperf for some examples.

I was going to start the testing for the second version of the series
just now.

This suggestion sounds great, let's see how it's going to look.


Cheers,
-- 
Vinicius
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