Re: Network performance degradation from 2.6.11.12 to 2.6.16.20

On Mon, 19 Jun 2006, Andi Kleen wrote:

quoted

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.

Sorry, it was not a general advice, just something to try out.  It really 
solved my network performance issue...

quoted

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.

I do not know what caused the issue on my machine, but I can look into it 
if you like to know?

I do have VLAN interfaces on the machine and it seems that eth1 runs in 
PROMISC mode (eth1.xxx does not).  Could it be caused by that?

Hilsen
   Jesper Brouer

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MSc. Master of Computer Science
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