From: Eric Dumazet <[EMAIL PROTECTED]> Date: Fri, 28 Sep 2007 00:08:33 +0200
> 1) It adds 48 bytes per 'struct tcp_sock' > 2) It adds some ugly code in hot paths > 3) It has a small hit ratio on typical servers using many sockets > 4) It may have a high hit ratio on UP machines running one process, > where the prequeue adds litle gain. (In fact, letting the user > doing the copy after being woke up is better for cache reuse) > 5) Doing a copy to user in softirq handler is not good, because of > potential page faults :( > 6) Maybe the NET_DMA thing is the only thing that might need prequeue. If you want to make changes at least get your facts straight in your changelog message :-) The prequeue doesn't do copies in softirqs, it acquires the user side socket lock and runs the packet input path directly from there, copying into userspace along the way. You are making claims about performance based upon your understanding of the code and your understanding of typical workloads, rather than from actual measurements. In scientific communities this would make you a quack at best :-) - 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
