From: Miklos Szeredi <[EMAIL PROTECTED]> Date: Wed, 06 Jun 2007 07:26:52 +0200
> > Holding a global mutex over recvmsg() calls under AF_UNIX is pretty > > much a non-starter, this will kill performance for multi-threaded > > apps. > > That's an rwsem held for read. It's held for write in unix_gc() only > for a short duration, and unix_gc() should only rarely be called. So > I don't think there's any performance problem here. It pulls a non-local cacheline into the local thread, that's extremely expensive on SMP. If everyone starts grabbing this thing during recvmsg() it's going to become a really hot lock and kill performance, even if it's a read side lock being taken. That's why I said we need to investigate solutions involving u->readlock, that already has to be taken and is local to the socket. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
