@Phillip: I would like to get to the root of your issue, but I don't know that this is the place to do it.
What is your processor? Mine is: Intel(R) Core(TM) i7-2600K CPU @ 3.40GHz What kernel version do you run? I am running 4.3RC1 with a modified intel_pstate driver. If I start a CPU burning process on CPU 7 I get: doug@s15:~/temp$ grep MHz /proc/cpuinfo cpu MHz : 3699.757 cpu MHz : 3627.640 cpu MHz : 3684.351 cpu MHz : 3800.429 cpu MHz : 3524.710 cpu MHz : 3522.187 cpu MHz : 3540.250 cpu MHz : 3799.898 Then if I set an upper limit: echo "75" | sudo tee /sys/devices/system/cpu/intel_pstate/max_perf_pct I get: doug@s15:~/temp$ grep MHz /proc/cpuinfo cpu MHz : 2799.953 cpu MHz : 2799.953 cpu MHz : 2799.953 cpu MHz : 2799.953 cpu MHz : 2853.078 cpu MHz : 2799.953 cpu MHz : 2799.953 cpu MHz : 2799.953 as expected. As a sanity check, my CPU prints a time message occasionally, so we would expect it to have a bigger gap between prints now: doug@s15:~/c$ taskset -c 7 ./test1 Elapsed: 174.06 s. Delta: 174.06 s. Ave (10): 17.41 s. user cpu: 173.88 s. sys cpu: 0.06 s. Elapsed: 348.04 s. Delta: 173.98 s. Ave (10): 34.80 s. user cpu: 347.74 s. sys cpu: 0.06 s. Elapsed: 557.31 s. Delta: 209.27 s. Ave (10): 55.73 s. user cpu: 556.88 s. sys cpu: 0.06 s. Elapsed: 792.06 s. Delta: 234.75 s. Ave (10): 79.21 s. user cpu: 791.47 s. sys cpu: 0.07 s. 174 / 235 = 74% -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1188647 Title: Please change intel_pstate default to disable To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1188647/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
