Re: Network performance degradation from 2.6.11.12 to 2.6.16.20
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From: Jesper Dangaard Brouer <hidden>
Date: 2006-06-19 14:47:52
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Harry Edmon [off-list ref] wrote:quoted
I have a system with a strange network performance degradation from 2.6.11.12 to most recent kernels including 2.6.16.20 and 2.6.17-rc6. The system is has Dual single core Xeons with hyperthreading on.
<cut> Hi Harry Can you check which "high-res timesource" you are using? In the kernel log look for: kernel: Using tsc for high-res timesource kernel: Using pmtmr for high-res timesource I have experinced some network performance degradation when using the "pmtmr" timesource, on a Opteron AMD system. It seems that the default timesource change between 2.6.15 to 2.6.16. If you use "pmtmr" try to reboot with kernel option "clock=tsc". 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). Cheers, Jesper Brouer -- ------------------------------------------------------------------- MSc. Master of Computer Science Dept. of Computer Science, University of Copenhagen Author of http://www.adsl-optimizer.dk -------------------------------------------------------------------