Looks like when CPUs going into a deep C state idle the latency jitter is low, but when we go into a deep idle on a HLT or WAIT we're taking a while to get active again.
With non-idle CPUs: ./clocktest Testing for clock jitter on 8 cpus PASSED: largest jitter seen was 0.000184 Testing clock direction for 5 minutes... PASSED: Iteration 0 delta: 0.000062 PASSED: Iteration 1 delta: 0.000059 PASSED: Iteration 2 delta: 0.000060 PASSED: Iteration 3 delta: 0.000058 PASSED: Iteration 4 delta: 0.000060 clock direction test: sleeptime 60 sec per iteration, failed iterations: 0 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1564949 Title: Severe latency/skew on AMD Opetron processor To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1564949/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs