Messages in this thread | | | Subject | Re: [PATCH] watchdog: Make sure the watchdog thread gets CPU on loaded system | From | Peter Zijlstra <> | Date | Thu, 15 Mar 2012 17:04:31 +0100 |
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On Thu, 2012-03-15 at 11:54 -0400, Don Zickus wrote: > > > Why did watchdog() reset the scheduling policy seven instructions > > > before exiting? Seems pointless. > > > > It has been introduced by Thomas in cba9bd22. To be honest I don't > > understand why it makes a sense? > > Yeah I noticed that too. I didn't bother questioning it either when > it > went in. I just assumed Thomas and Peter know scheduling a lot better > than I do. :-)
I just dug through my IRC logs and the reason is that running the entire exit path as a highest priority RT task incurs a latency spike to other tasks running on the system (313us). Since there's absolutely no point in running the exit path as a RT task, tglx made it not do that.
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