Hi,
I am having issues with performance in xen, to the tune of 20-30%!
I first noticed this when doing a kernel compile that seemed to take
slightly longer than expected, then in a benchmark that was 25% slower. I
also noticed that the max power draw was slightly lower, and the idle power
draw was slightly higher
In native linux, `cpufreq-info` shows that most cpus idle between 0.8 and
1.4GHz, and run with loads at 4.8GHz
In dom0 linux under xen, `xenpm get-cpufreq-states` shows that most cpus
idle at 2.2GHz, and run with loads at 4.2GHz
I tried adjusting the governor, but xen was still capped at 4.2GHz
I have a Threadripper 7960X on a ASRock TRX50 WS, and I can reproduce this
in xen 4.14, 4.17, and 4.18, and with Linux kernels 5.10 and 6.1. The
latter is from a brand-new debian 12 install.
What configuration or tuning should I look at to better utilize the
frequency range?
Thanks,
Patrick
I am having issues with performance in xen, to the tune of 20-30%!
I first noticed this when doing a kernel compile that seemed to take
slightly longer than expected, then in a benchmark that was 25% slower. I
also noticed that the max power draw was slightly lower, and the idle power
draw was slightly higher
In native linux, `cpufreq-info` shows that most cpus idle between 0.8 and
1.4GHz, and run with loads at 4.8GHz
In dom0 linux under xen, `xenpm get-cpufreq-states` shows that most cpus
idle at 2.2GHz, and run with loads at 4.2GHz
I tried adjusting the governor, but xen was still capped at 4.2GHz
I have a Threadripper 7960X on a ASRock TRX50 WS, and I can reproduce this
in xen 4.14, 4.17, and 4.18, and with Linux kernels 5.10 and 6.1. The
latter is from a brand-new debian 12 install.
What configuration or tuning should I look at to better utilize the
frequency range?
Thanks,
Patrick