Messages in this thread | | | Subject | Re: [RFC 3/5] sched: Add CPU rate hard caps | From | Mike Galbraith <> | Date | Fri, 26 May 2006 16:23:18 +0200 |
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On Fri, 2006-05-26 at 23:59 +1000, Peter Williams wrote: > Con Kolivas wrote: > > On Friday 26 May 2006 14:20, Peter Williams wrote: > >> This patch implements hard CPU rate caps per task as a proportion of a > >> single CPU's capacity expressed in parts per thousand. > > > > A hard cap of 1/1000 could lead to interesting starvation scenarios where a > > mutex or semaphore was held by a task that hardly ever got cpu. Same goes to > > a lesser extent to a 0 soft cap. > > > > Here is how I handle idleprio tasks in current -ck: > > > > http://ck.kolivas.org/patches/2.6/pre-releases/2.6.17-rc5/2.6.17-rc5-ck1/patches/track_mutexes-1.patch > > tags tasks that are holding a mutex > > > > http://ck.kolivas.org/patches/2.6/pre-releases/2.6.17-rc5/2.6.17-rc5-ck1/patches/sched-idleprio-1.7.patch > > is the idleprio policy for staircase. > > > > What it does is runs idleprio tasks as normal tasks when they hold a mutex or > > are waking up after calling down() (ie holding a semaphore). > > I wasn't aware that you could detect those conditions. They could be > very useful.
Isn't this exactly what the PI code is there to handle? Is something more than PI needed?
-Mike
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