https://bugzilla.novell.com/show_bug.cgi?id=826946 https://bugzilla.novell.com/show_bug.cgi?id=826946#c0 Summary: CONFIG_NO_HZ_FULL=y in Kernel:Head/kernel-desktop causing high power usage due to CPU 0 POLL 100 % Classification: openSUSE Product: openSUSE Factory Version: 13.1 Milestone 2 Platform: x86-64 OS/Version: openSUSE 12.3 Status: NEW Severity: Normal Priority: P5 - None Component: Kernel AssignedTo: kernel-maintainers@forge.provo.novell.com ReportedBy: nine@detonation.org QAContact: qa-bugs@suse.de Found By: --- Blocker: --- User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.21 (KHTML, like Gecko) rekonq/2.3.1 Safari/537.21 Using a kernel-desktop 3.10 from Kernel:HEAD causes high power usage (> 20 W instead of 9 W on my laptop). According to powertop CPU 0 is spending almost all its time in active / POLL instead of one of the power saving states. The cause seems to be CONFIG_NO_HZ_FULL=y. I recompiled the kernel with CONFIG_NO_HZ_IDLE=y instead (everything else the same) and power usage went back to normal with most of the time spent in C6-IVB (on my desktop). Seen this problem on a Core i5 Sandybridge and a Core i7 Ivybridge. Since CONFIG_NO_HZ_FULL is not recommended anyway, I'd suggest changing the config at least for kernel-desktop. Reproducible: Always Steps to Reproduce: 1. boot a kernel-desktop-3.10 from Kernel:HEAD 2. start powertop 3. switch to the Idle tab Actual Results: CPU 0 100 % active even without any processes running Expected Results: CPU 0 saving power like the other cores -- Configure bugmail: https://bugzilla.novell.com/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.