>> Hi, Aaron
>>
>> 1)
>> I talked with Marcelo about this one.
>> He said it might be related with cacheline. the new field distroyed
>> the prior cacheline. So on top of commit 826d253d57b1, pls only add
>> + unsigned long prsctp_param;
>>
>> to the end of struct sctp_chunk, then try.
>
> This doesn't work.
>
If it's because of cache lines changed, I'm not sure this, either.
Maybe 2) is a good way to fix it.
Thanks Aaron.
>> 2)
>> if 1) still doesn't work, I may think about to drop prsctp_param in
>> sctp_chunk, and reuse msg->expire_at. as for sent_count, I will
>> put it to the mem hole of sctp_chunk.
>>
>> So pls also try the attachment patch, on top of commit a6c2f792873a
>
> Good news, this brings the performance back on my Sandybridge desktop :)
> I have queued jobs to the Ivybridge test box but I guess the result is
> the same, but will let you know if it isn't.
>
> It looks like the size of the structure plays a role here, but not clear
> to me what happened underneath. Do you know why?
>
> Thanks,
> Aaron
>
>>
>> Thanks.
>
>> diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
>> index 6bcda71..008cb76 100644
>> --- a/include/net/sctp/structs.h
>> +++ b/include/net/sctp/structs.h
>> @@ -524,7 +524,11 @@ struct sctp_datamsg {
>> struct list_head chunks;
>> /* Reference counting. */
>> atomic_t refcnt;
>> - /* When is this message no longer interesting to the peer? */
>> + /* Re-use this field to record param for prsctp policies,
>> + * for TTL policy, it is the time_to_drop of this chunk,
>> + * for RTX policy, it is the max_sent_count of this chunk,
>> + * for PRIO policy, it is the priority of this chunk.
>> + */
>> unsigned long expires_at;
>> /* Did the messenge fail to send? */
>> int send_error;
>> @@ -553,6 +557,9 @@ struct sctp_chunk {
>>
>> atomic_t refcnt;
>>
>> + /* How many times this chunk have been sent, for prsctp RTX policy */
>> + int sent_count;
>> +
>> /* This is our link to the per-transport transmitted list. */
>> struct list_head transmitted_list;
>>
>> @@ -602,16 +609,6 @@ struct sctp_chunk {
>> /* This needs to be recoverable for SCTP_SEND_FAILED events. */
>> struct sctp_sndrcvinfo sinfo;
>>
>> - /* We use this field to record param for prsctp policies,
>> - * for TTL policy, it is the time_to_drop of this chunk,
>> - * for RTX policy, it is the max_sent_count of this chunk,
>> - * for PRIO policy, it is the priority of this chunk.
>> - */
>> - unsigned long prsctp_param;
>> -
>> - /* How many times this chunk have been sent, for prsctp RTX policy */
>> - int sent_count;
>> -
>> /* Which association does this belong to? */
>> struct sctp_association *asoc;
>>
>> diff --git a/net/sctp/chunk.c b/net/sctp/chunk.c
>> index 2698d12..0c53d64 100644
>> --- a/net/sctp/chunk.c
>> +++ b/net/sctp/chunk.c
>> @@ -349,7 +349,7 @@ int sctp_chunk_abandoned(struct sctp_chunk *chunk)
>> }
>>
>> if (SCTP_PR_TTL_ENABLED(chunk->sinfo.sinfo_flags) &&
>> - time_after(jiffies, chunk->prsctp_param)) {
>> + time_after(jiffies, chunk->msg->expires_at)) {
>> if (chunk->sent_count)
>> chunk->asoc->abandoned_sent[SCTP_PR_INDEX(TTL)]++;
>> else
>> diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
>> index 2c431ee..c7110a9 100644
>> --- a/net/sctp/sm_make_chunk.c
>> +++ b/net/sctp/sm_make_chunk.c
>> @@ -718,7 +718,7 @@ static void sctp_set_prsctp_policy(struct sctp_chunk
>> *chunk,
>> return;
>>
>> if (SCTP_PR_TTL_ENABLED(sinfo->sinfo_flags))
>> - chunk->prsctp_param =
>> + chunk->msg->expires_at =
>> jiffies + msecs_to_jiffies(sinfo->sinfo_timetolive);
>> }
>>
>
