From: Eric Dumazet <[EMAIL PROTECTED]> Date: Thu, 08 Dec 2005 04:47:05 +0100
> #4#5 as proposed in the patch can not be a win > > + prefetch(next_skb); > + prefetch(next_skb->data - NET_IP_ALIGN); > > because at the time #5 is done, the CPU dont have in its cache next_skb->data > (because the #4 prefetch is the previous instruction) > > prefetch(ptr) is mostly a free hint for the CPU. > > prefetch(*ptr) can be expensive because of the needed indirection that might > slow down the CPU if *ptr is not yet available in its L1 cache. Agreed. Doing a depdant prefetch back to back so close like that is nearly pointless. - 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
