> -----Original Message-----
> From: Eelco Chaudron <[email protected]>
> Sent: Thursday, July 8, 2021 11:48 AM
> To: Ferriter, Cian <[email protected]>
> Cc: [email protected]; [email protected]; [email protected]; Van
> Haaren, Harry <[email protected]>; Amber, Kumar
> <[email protected]>; Stokes, Ian <[email protected]>
> Subject: Re: [v6 06/11] dpif-netdev: Add packet count and core id paramters 
> for
> study
> 
> On 6 Jul 2021, at 15:11, Cian Ferriter wrote:
> 
> > From: Kumar Amber <[email protected]>
> >
> > This commit introduces additional command line paramter
> > for mfex study function. If user provides additional packet out
> > it is used in study to compare minimum packets which must be processed
> > else a default value is choosen.
> > Also introduces a third paramter for choosing a particular pmd core.
> >
> > $ ovs-appctl dpif-netdev/miniflow-parser-set study 500 3
> >
> > Signed-off-by: Kumar Amber <[email protected]>
> 
> 
> When doing some testing I ran into another corner case. If I start one PMD 
> with
> packet count 1000, and then another with packet count 10. Both will use 10, as
> the packet count value, as is stored globally.

Valid corner case, good point, indeed the value is stored globally.

The packet-count for study was designed/added as a way to avoid studying
too many (overhead) or too few (inaccuracy) packets. I'm not sure how useful
it *actually is* in real-world.

Would documenting "the per packet count" is a global value, and parallel 
`study()`
executions with differing packet counts will use the most recent count value" 
be acceptable?

In any given scenario, I expect the "pkt_cnt" value to be the same for all PMD
threads as variance in traffic is likely to be constant for all PMD-threads 
(particularly
since auto-load-balancing of rxq/pmds is being improved). A single global value 
being
used covers all my known use-cases.

Thoughts?

> > ---
> < SNIP>

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