On Wed, 2011-12-14 at 00:28 +0100, Thomas Gleixner wrote: > On Wed, 14 Dec 2011, Benjamin Herrenschmidt wrote: > > > On Tue, 2011-12-13 at 12:42 -0800, Fushen Chen wrote: > > > On APM82181, "vmstat" (/proc/stat) doesn't show correct idle > > > percent, if kernel enables "CONFIG_NO_HZ" (Tickless System / Dynamic > > > Tick). > > > > > > When I run wireless throughput test with heavy traffic, "vmstat" shows > > > very high idle percent while "oprofile" shows very low idle percent. > > > During the test, the system is idle, but network traffic uses a lot of > > > hard IRQ and soft-irq time. "vmstat" would have the correct stats if > > > account_idle_ticks(ticks) in kernel/time/tick-sched.c doesn't add more > > > idle time in "vmstat". In the same test, if I disable "CONFIG_NO_HZ" > > > in kernel, idle percent in "vmstat" and "oprofile" would match. > > > > > > My APM82181 kernel configuration is "CONFIG_NO_HZ", "CONFIG_HZ_250=y", > > > "CONFIG_HZ=250", and "CONFIG_HIGH_RES_TIMERS". > > > > > > My question is that if kernel enables "CONFIG_NO_HZ", how would kernel > > > report correct stats. > > > > Hi Thomas ! Any idea what we're doing wrong ? :-) > > Not really, that had been an issue before and had been fixed. Peter ????
Fusen, what kernel version is this ? Cheers, Ben. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
