Re: [LKP] [lkp] [sctp] a6c2f79287: netperf.Throughput_Mbps -37.2% regression

[Xin Long]

>  include/net/sctp/structs.h | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
> index d8e464aacb20..932f2780d3a4 100644
> --- a/include/net/sctp/structs.h
> +++ b/include/net/sctp/structs.h
> @@ -602,6 +602,9 @@ struct sctp_chunk {
>         /* This needs to be recoverable for SCTP_SEND_FAILED events. */
>         struct sctp_sndrcvinfo sinfo;
>
> +       unsigned long prsctp_param;
> +       int sent_count;
> +
>         /* Which association does this belong to?  */
>         struct sctp_association *asoc;
>
> --
> 2.5.5
>
> Then the performance dropped to the same as the bisected commit
> a6c2f792873a:
> $ cat 4.7.0-rc6-01198-g98dd2532b14e/0/netperf.json
> {
>   "netperf.Throughput_Mbps": [
>    754.494375
>   ]
> }
>
> I think this agrees with the perf data in that the newly added function
> doesn't show up in the perf-profile but still, the performance drops.
> So the only possible reason is the newly added fields to the sctp_chunk
> structure.
>
> Is this expected?
interesting , you didn't include the modification of the functions
parts, right ?
you mean only this two line:
> +       unsigned long prsctp_param;
> +       int sent_count;ca;

caused the performance issue ?