Quoting r. Roland Dreier <[EMAIL PROTECTED]>: > Subject: Re: [PATCH] ipoib: dont lock tx on completion > > Michael> By testing again, and waking the net queue if completions > Michael> arrived, we can avoid taking the tx lock on send > Michael> completion in ip over ib, reducing the lock contention. > > I really like the clever way of retesting after putting the queue to > sleep. However I can't convince myself that some test or other will > be wrong because of stale values of tx_head or tx_tail,
Not sure what is meant here by "stale values". This is the usual consumer/producer approach ... > and I'm always > scared of code that requires multiple barriers and so on. So I'm > going to defer applying this until I have time to think hard and make > sure there aren't any subtle races. > > - R. > Okay. Also note that the exact value of tx_tail/tx_head should not practially matter, since to change the state you have to go from half-full TX queue to full TX queue, or back. There will be a huge number barriers, locks etc done by that time. MST -- 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
