On Thu, 2014-02-27 at 21:20 -0800, Andi Kleen wrote:

Eric Dumazet [off-list ref] writes:

quoted

 
-	rtt_update = tcp_ack_update_rtt(sk, flag, seq_rtt, sack_rtt);
+	if (first_ackt.tv64) {
+		ktime_t curt = ktime_get_real();

Sorry I'm late to the party. One problem is that if a system doesn't use
TSC for some reason this will be incredibly slow (unfortunately this
happens for various reasons). Perhaps we need a
ktime_get_real_but_use_jiffies_if_slow() or somesuch.

Right, so I cooked this instead :

http://git.kernel.org/cgit/linux/kernel/git/davem/net-next.git/commit/?id=363ec392352e55c61ce2799c3f15f89f9429bba7

Is this OK or do you see a problem with this ?

Thanks !