On Fri, 2012-11-02 at 21:09 +0100, Michal Zatloukal wrote: > On the new kernel, the nice processes are never starved - even when > starting a tab-laden chromium session, the processes for BOINC keep > about 20% CPU each (that is normalized to all CPUs, ie 40% nice load > on each core). The problem is, the governor now seems to consider the > non-nice task unable to saturate the CPU, and the cores' frequencies > are hovering between 1.0 and 1.8 GHz. The scheduler keeps scheduling > the nice tasks, and the non-nice tasks are progressing much slower, > caused by the lower CPU speed as well as less processing time > allocated to them. HD video stutters often, and Chromium takes at > least 2-3 times longer to fully load. Your nice 19 tasks receiving 'too much' CPU when there are other runnable tasks around sounds like you have SCHED_AUTOGROUP enabled. With this enabled (or if tasks are placed in cgroups by another means), group A and group B will each receive equal CPU if group shares/weight are equal, regardless of group content. Task nice level will affect CPU distribution within a group, but group A containing a gaggle of nice 19 tasks will receive the same amount of CPU as group B containing your nice 0 browser with zillion tabs. Add nice 0 hogs to group A, the nice 19 tasks will receive much less CPU, but the total for group A will remain unchanged relative to group B, unless group shares/weights are twiddled. (no idea what's going on with ondemand) -Mike -- 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
