Quoting r. Roland Dreier <[EMAIL PROTECTED]>: > Subject: Re: [openib-general] [PATCH] 2/2 : ip over ib tx/rx split > > Michael> I'm reposting this patch, its now tested. Together with > Michael> the first part: mthca send/receive q lock split, I am > Michael> getting about 2% more bandwidth with this patch. I also > Michael> checked interrupt rate and it is about the same, which is > Michael> not surprising, since interrupts from both cqs are > Michael> coalesced by the eq polling in mthca. > > Do you see any improvement with just the QP lock split and a single > CQ? It seems to me that the boost comes from being able to handle > completions from one work queue while posting work requests to the > other queue.
Didnt test that. > I don't see how having two CQs helps reduce lock > contention or improve parallelism at all. There's still only one > interrupt handler and one IPoIB completion event handler, which can > only run on one CPU. So it seems what will happen is: > > EQ event > Find EQE for receive CQ > Lock receive CQ, process completions > Unlock receive CQ > Find EQE for send CQ > Lock send CQ, process completions > Unlock send CQ > > The only difference is that we unlock the receive CQ and lock the send > CQ in the middle. Are you sure? I *do* have msi-x on these machines. > > Especially since you say the interrupt rate is the same, it seems that > almost all the time, the completion event handler is finding > completions in both queues anyway. > > - R. > -- MST - Michael S. Tsirkin _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
