On 08/18/2010 11:20 PM, LionSky wrote: > Hi all, > Recently, I used PowerTop to tune an workload power behavior, but > found a new interrupt(TLB shootdowns) from its wakeups list as > follows: > > Top causes for wakeups: > 66.2% (1806.2) [ 0] [kernel scheduler] Load balancing tick > 16.5% (451.1) [ ] [TLB shootdowns]<kernel IPI> > 9.8% (267.7)D [ ] chrome > 4.5% (121.5) [ ] [Rescheduling interrupts]<kernel IPI> > 1.7% ( 46.9) [ ] [hda_intel]<interrupt> > 0.8% ( 23.2) [ ] [i915]<interrupt> > 0.0% ( 0.1)D [ 78] btrfs-transacti > 0.2% ( 4.9) [ 737] syndaemon > 0.1% ( 1.9) [ ] [ahci]<interrupt> > > There is about 450 TLB shootdowns interrupt per second, so high. .. > I searched google for help, but only found what is TLB shootdowns: > "A TLB Shootdown occurs when a process restricts access to a page in > shared memory and must interrupt processes using that memory space on > other processors so they flush their TLB tables" > > I have no idea whether "TLB shootdowns" interrupt has any impact on > power, or even workload's performance. > Do anyone have some idea about that?
TLB shootdowns are caused by an application in essence, and will indeed cause an impact on power. The most likely culprit is some memory-hungry application(chrome?) forcing pages to be swapped out (or something similar) that were shared between cores, and so each core now needs to update, keeping them out of a deeper C-state. Auke _______________________________________________ Power mailing list [email protected] http://www.bughost.org/mailman/listinfo/power
