Re: CONFIG_NO_HZ_FULL restricts cpu usage to the equivalent of one in 4.2

2015-07-18 Thread Frederic Weisbecker
On Thu, Jul 16, 2015 at 01:32:18AM +0100, Ken Moffat wrote: > On Wed, Jul 15, 2015 at 09:11:46PM +0200, Frederic Weisbecker wrote: > > 2015-07-15 18:27 GMT+02:00 Ken Moffat : > > > > > > The config differences follow. Perhaps it is actually one of the > > > subsequent choices that is the problem.

Re: CONFIG_NO_HZ_FULL restricts cpu usage to the equivalent of one in 4.2

2015-07-15 Thread Ken Moffat
On Wed, Jul 15, 2015 at 12:05:05PM -0700, Andy Lutomirski wrote: > > Before going nuts bisecting, it could be worth running perf record -a -g -e > cycles (or perhaps -e task-clock instead of -e cycles). It could also be > worth manually sampling /proc/PID/stack a few times for a process that isn'

Re: CONFIG_NO_HZ_FULL restricts cpu usage to the equivalent of one in 4.2

2015-07-15 Thread Ken Moffat
On Wed, Jul 15, 2015 at 09:11:46PM +0200, Frederic Weisbecker wrote: > 2015-07-15 18:27 GMT+02:00 Ken Moffat : > > > > The config differences follow. Perhaps it is actually one of the > > subsequent choices that is the problem. And I guess it could still > > be a gcc-5.1 issue. > > > > --- config

Re: CONFIG_NO_HZ_FULL restricts cpu usage to the equivalent of one in 4.2

2015-07-15 Thread Frederic Weisbecker
2015-07-15 18:27 GMT+02:00 Ken Moffat : > New title, I originally posted this last night but I've now made > a little progress in identifying what changed. Previous thread was > labelled for AMD Phenom, but it is more general. CC'ing Jeff > because he replied to the original, I guess he probably

Re: CONFIG_NO_HZ_FULL restricts cpu usage to the equivalent of one in 4.2

2015-07-15 Thread Andy Lutomirski
On 07/15/2015 09:27 AM, Ken Moffat wrote: New title, I originally posted this last night but I've now made a little progress in identifying what changed. Previous thread was labelled for AMD Phenom, but it is more general. CC'ing Jeff because he replied to the original, I guess he probably won'

CONFIG_NO_HZ_FULL restricts cpu usage to the equivalent of one in 4.2

2015-07-15 Thread Ken Moffat
New title, I originally posted this last night but I've now made a little progress in identifying what changed. Previous thread was labelled for AMD Phenom, but it is more general. CC'ing Jeff because he replied to the original, I guess he probably won't be interested after this. Yesterday was t