On Tue, Jan 10, 2023 at 2:47 PM Kevin Traynor <[email protected]> wrote:
>
> Sleep for an incremental amount of time if none of the Rx queues
> assigned to a PMD have at least half a batch of packets (i.e. 16 pkts)
> on an polling iteration of the PMD.
>
> Upon detecting the threshold of >= 16 pkts on an Rxq, reset the
> sleep time to zero (i.e. no sleep).
>
> Sleep time will be increased on each iteration where the low load
> conditions remain up to a total of the max sleep time which is set
> by the user e.g:
> ovs-vsctl set Open_vSwitch . other_config:pmd-maxsleep=500
>
> The default pmd-maxsleep value is 0, which means that no sleeps
> will occur and the default behaviour is unchanged from previously.
>
> Also add new stats to pmd-perf-show to get visibility of operation
> e.g.
> ...
>    - sleep iterations:       153994  ( 76.8 % of iterations)
>    Sleep time (us):         9159399  ( 46 us/iteration avg.)
> ...
>
> Signed-off-by: Kevin Traynor <[email protected]>
> Reviewed-by: Robin Jarry <[email protected]>

This v4 updates lgtm.
I just have one nit.

[snip]

> +Example output, showing that during the last 10 seconds, 76.8% of iterations
> +had a sleep of some length. The total amount of sleep time was 9.15 seconds 
> and
> +the average sleep time per iteration was 46 microseconds::
> +
> +   - sleep iterations:       153994  ( 76.8 % of iterations)
> +   Sleep time:               9159399  us ( 46 us/iteration avg.)

This output is not aligned with v4 code.


> +
> +Any potential power saving from PMD load based sleeping is dependent on the
> +system configuration (e.g. enabling processor C-states) and workloads.
> +

Reviewed-by: David Marchand <[email protected]>


-- 
David Marchand

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