Could it be related to this: https://www.phoronix.com/scan.php?page=news_item&px=P-State-Possible-4.6-Regression
On Thu, 16 Jun 2016 18:40:01 +0200 Jirka Hladky <jhla...@redhat.com> wrote: > Hello, > > we see performance drop 30-40% for SPECjbb2005 and SPECjvm2008 > benchmarks starting from 4.7.0-0.rc0 kernel compared to 4.6 kernel. > > We have tested kernels 4.7.0-0.rc1 and 4.7.0-0.rc3 and these are as > well affected. > > We have observed the drop on variety of different x86_64 servers with > different configuration (different CPU models, RAM sizes, both with > Hyper Threading ON and OFF, different NUMA configurations (2 and 4 > NUMA nodes) > > Linpack and Stream benchmarks do not show any performance drop. > > The performance drop increases with higher number of threads. The > maximum number of threads in each benchmark is the same as number of > CPUs. > > We have opened a BZ to track the progress: > https://bugzilla.kernel.org/show_bug.cgi?id=120481 > > You can find more details along with graphs and tables there. > > Do you have any hints which commit should we try to reverse? > > Thanks a lot! > Jirka