On Fri, 17 Apr 2015 14:37:17 -0400 Chris Metcalf <cmetc...@ezchip.com> wrote:
> Change the default behavior of watchdog so it only runs on the > housekeeping cores when nohz_full is enabled at build and boot time. > Allow modifying the set of cores the watchdog is currently running > on with a new kernel.watchdog_cpumask sysctl. > > If we allowed the watchdog to run on nohz_full cores, the timer > interrupts and scheduler work would prevent the desired tickless > operation on those cores. But if we disable the watchdog globally, > then the housekeeping cores can't benefit from the watchdog > functionality. So we allow disabling it only on some cores. > See Documentation/lockup-watchdogs.txt for more information. Could you please expand on the patch motivation? "would prevent the desired tickless operation on those cores" is quite vague. Exactly what userspace-visible problem is the current implementation causing and how does the patchset improve things? If any of this is quantifiable (wakeups/sec, joules/hour etc) then some attempt to perform those measurements would also be useful. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
