On Friday 09 February 2007 09:40, David Miller wrote: > From: Andi Kleen <[EMAIL PROTECTED]> > Date: 09 Feb 2007 10:18:03 +0100 > > > David Miller <[EMAIL PROTECTED]> writes: > > > I've applied this, but I _REALLY_ don't like the new multiply > > > instructions that are used now in the hash indexing paths when > > > CONFIG_SMP is set. > > > > > > I think that's a higher cost than the memory waste. > > > > You're serious? multiply on a modern CPU is _much_ cheaper than a cache > > miss e.g. a K8 can do a arbitary 64bit multiplication in 3-7 cycles. > > Any cache miss will be in the three to four digits at least. > > I'm not thinking of modern CPUs, I'm think of the little > guys :-)
Yes, but a decent C compiler for such targets should not use a multiply instruction to perform a (idx * 12) operation... :) - 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
