http://bugzilla.kernel.org/show_bug.cgi?id=12310 Summary: NOHZ appears to cause ondemand to effectively ignore 'ignore_nice_load' Product: Power Management Version: 2.5 KernelVersion: 2.6.28 Platform: All OS/Version: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: cpufreq AssignedTo: cpufreq@xxxxxxxxxxxxxxx ReportedBy: jimsantelmo@xxxxxxxxx Latest working kernel version: Don't think it ever worked well with NOHZ, but got worse after 2.6.26 Earliest failing kernel version: Distribution: Hardware Environment: Everex notebook, AMD 64 dual-core Software Environment: Problem Description: [this bug is a tickless+ondemand interaction: the problem may be in the cpufreq_ondemand code] I'm running boinc, which will cheerfully keep both cores loaded with niced processes if I let it. In the past, meaning for the last six months or more, I managed to stop the niced processes from upping the frequency by setting up_threshhold to 50 or more and letting boinc use only 80% CPU, but with 2.6.28 nothing I did mattered. I got to looking around the ondemand code and noticed that it would try to call get_cpu_idle_time_us() and then calculate idle time differently if that failed, which would happen if NOHZ is turned off. I rebooted with 'nohz=off' and the ondemand code behaves completely to spec according to how I set ignore_nice_load and up_threshhold. Steps to reproduce: Build tickless kernel, run boinc (or maybe a niced while-true loop?). -- Configure bugmail: http://bugzilla.kernel.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug, or are watching the assignee. -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
