On Wed, 8 Nov 2006 23:10:28 +0100 Olaf Kirch <[EMAIL PROTECTED]> wrote:
> On Wed, Nov 08, 2006 at 10:38:52AM -0800, Tim Chen wrote: > > The patch in question affects purely TCP and not the scheduler. I don't > > I know. > > > think the scheduler has anything to do with the slowdown seen after > > the patch is applied. > > In fixing performance issues, the most obvious explanation isn't always > the right one. It's quite possible you're right, sure. > > What I'm saying though is that it doesn't rhyme with what I've seen of > Volanomark - we ran 2.6.16 on a 4p Intel box for instance and it didn't > come close to saturating a Gigabit pipe before it maxed out on CPU load. > > > The total number of messages being exchanged around the chatrooms in > > Volanomark remain unchanged. But ACKS increase by 3.5 times and > > segments received increase by 38% from netstat. > > > So I think it is reasonable to conclude that the increase in TCP traffic > > reduce the bandwidth and throughput in Volanomark. > > You could count the number of outbound packets dropped on the server. > > Olaf Also under benchmark stress, the load can get so high that timers go off that normally don't. For example, I have seen delayed ack timer cause extra ack's when at lower loads the response happened quick enough that the ACK was piggybacked. -- 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
