Hi Andi, 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. > > > > > 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 encountered the same problem on a dual core opteron equipped with a broadcom NIC (tg3) under 2.4. It could receive 1 Mpps when using TSC as the clock source, but the time jumped back and forth, so I changed it to 'notsc', then the performance dropped dramatically to around the same value as above with one CPU saturated. I suspect that the clock precision is needed by the tg3 driver to correctly decide to switch to polling mode, but unfortunately, the performance drop rendered the solution so much unusable that I finally decided to use it only in uniprocessor with TSC enabled. > -Andi Regards, Willy - 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
