[lkml]   [2006]   [Sep]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: Network performance degradation from to
On Mon, Jun 19, 2006 at 05:24:31PM +0200, Andi Kleen wrote:
> > If you use "pmtmr" try to reboot with kernel option "clock=tsc".
> That's dangerous advice - when the system choses not to use
> TSC it often has a reason.

I just found out that TSC clocksource is not implemented on x86-64.
Kernel version 2.6.18-rc7, is it true?

I've also had experience of unsychronized TSC on dual-core Athlon,
but it was cured by idle=poll.

> >
> > On my Opteron AMD system i normally can route 400 kpps, but with
> > timesource "pmtmr" i could only route around 83 kpps. (I found the timer
> > to be the issue by using oprofile).
> Unless you're using packet sniffing or any other application
> that requests time stamps on a socket then the timer shouldn't
> make much difference. Incoming packets are only time stamped
> when someone asks for the timestamps.
It seems that dhcpd3 makes the box timestamping incoming packets,
killing the performance. I think that combining router and DHCP server
on a same box is a legitimate situation, isn't it?

With best regards,
Vladimir Savkin.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2006-09-16 14:11    [W:0.138 / U:7.824 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site