Messages in this thread | | | Date | Thu, 18 Aug 2016 11:21:56 +0800 | From | Aaron Lu <> | Subject | Re: [LKP] [lkp] [sctp] a6c2f79287: netperf.Throughput_Mbps -37.2% regression |
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On Thu, Aug 18, 2016 at 02:06:50AM +0800, Xin Long wrote: > > > > It doesn't seem memory is an issue. > > > > The whole dump is about the same. > > The MemFree and MemAvailable doesn't change much. > > > 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.
> 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); > } >
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