On Mon, 2016-09-26 at 19:48 -0500, Larry Finger wrote: > On 09/26/2016 07:21 PM, Rafael J. Wysocki wrote: > > > > On Tue, Sep 27, 2016 at 1:53 AM, Larry Finger <Larry.Finger@lwfinge > > r.net> wrote: > > > > > > On 09/26/2016 05:16 PM, Rafael J. Wysocki wrote: > > > > > > > > > > > > On Tue, Sep 27, 2016 at 12:09 AM, Larry Finger > > > <larry.fin...@lwfinger.net> wrote: > > > > > > > > > > > > > > > > Maybe it's better to try diagnose the problem instead of > > > > spending more > > > > time on bisection. > > > > > > In my original post, I asked for such help, but nothing until > > > today. I had > > > no idea what to check, but now I have a better idea. > > > > > > > > > > > I'd like to know whether or not 4.7 was definitely good, > > > > though. > > > > > > I never saw this problem with 4.7, but given the difficulty in > > > triggering > > > the problem, my tests may not have been definitive. > > > > > > > > > > > > > > > > > > > > > > If it is one of them, it may be a while before I dare call > > > > > this one > > > > > "good". > > > > > In one respect, that is good as I will be traveling tomorrow > > > > > and > > > > > Wednesday. > > > > > > > > What does "cat > > > > /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver" say? > > > > > > intel_pstate > > You probably don't need to worry about all of the cpufreq changes > > in > > 4.8-rc, then. Only a few of them affect intel_pstate and I don't > > see > > how any of them may lead to the observed symptoms. > > > > First off, if you have a reproducer, please run it on 4.7 and see > > if > > you can trigger the issue in there. > I'm running 4.8-rc7 at the moment hoping to trigger the problem and > get the data > requested by Srinivas. Once I get that, I will try 4.7 again. > > > > > > Second, it would be good to have a look at the output from the > > cpu_frequency and pstate_sample tracepoints around when the issue > > triggers. The pstate_sample one would be more interesting. > > > > But for both we need a reproducer anyway. > I do not have a reliable reproducer. The condition has always > happened when > running a high-compute job such as a 'make -j8' on the kernel, or > building the > RPM for openSUSE's implementation of VirtualBox. The latter is what > I'm using > for most of my testing. > > > > > It also would be good to rule out the thermal throttling (as per > > the > > Srinivas' comments). > > > > For now, please tell me what's in > > /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq > 800000 Your effective freq is lower than 800MHz. One of the possible reason is thermal throttling.
What distro you are using? Thanks, Srinivas