[ltp] Temperature increase after S2Ram

Paul Bolle linux-thinkpad@linux-thinkpad.org
Sun, 07 Jul 2013 10:52:51 +0200

On Sun, 2013-07-07 at 02:47 -0300, Henrique de Moraes Holschuh wrote:
> This is not the first report that 3.10 is a dud.  Make extremely sure you
> have _NOT_ enabled the new "full tickless" mode, that thing is broken to
> kingdon come [either that, or it gets all zombies to come out in the open].

I currently use
    $ grep NO_HZ /boot/config-3.10.0-1.local0.fc18.x86_64 
    # CONFIG_NO_HZ_FULL is not set
    # CONFIG_RCU_FAST_NO_HZ is not set

So the new full tickless mode is disabled, isn't it?

> Check with powertop

Somehow it seems powertop triggers Heisenbug behavior! If the second
core is apparently stuck at 2 GHz, and I start powertop to see what's
going on, the second core will again drop down to 800 MHz, eventually.
But quitting powertop makes the second core jump to 2 GHz again (judging
by /proc/cpuinfo's output, that is).

That is strange! So let's assume for now that I see patterns that just
aren't there. Ie, this needs more testing on my side.

> and turbostat
    $ sudo ./turbostat -S
    No invariant TSC

>  to make sure the cores are idling
> properly (i.e. hitting c3 and c6), as well.

Paul Bolle