On Fri, 28 Sep 2007 00:08:33 +0200 Eric Dumazet <[EMAIL PROTECTED]> wrote:
> Hi all > > I am sure some of you are going to tell me that prequeue is not > all black :) > > Thank you > > [RFC] Make TCP prequeue configurable > > The TCP prequeue thing is based on old facts, and has drawbacks. > > 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. > > This patch introduces a CONFIG_TCP_PREQUEUE, automatically selected if > CONFIG_NET_DMA is on. > > Signed-off-by: Eric Dumazet <[EMAIL PROTECTED]> > Rather than having a two more compile cases and test cases to deal with. If you can prove it is useless, make a case for killing it completely. -- Stephen Hemminger <[EMAIL PROTECTED]> - 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
