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RFC use virtual time for CFS on s390

Jan Glauber lkml 1 version New

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  1. v1 RFC Latest2 patches 0 repliesNew

Patches in v1 No applies recorded yet

#Subject and filesSizeRepliesApplied
1/2virtual sched_clock() for s390arch/s390/kernel/time.c arch/s390/kernel/vtime.c include/asm-s390/timer.h+70 -140 replies
2/2base scheduler_tick() on virtual timearch/s390/kernel/time.c arch/s390/kernel/vtime.c include/asm-s390/lowcore.h +1 more+16 -70 replies

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Cover letter [RFC PATCH 0/2] use virtual time for CFS on s390

Hi Ingo,

an outcome from the previous discussion about a virtual sched_clock() on s390 was that scheduler_tick() should also be called based on virtual time. The second patch changes the scheduler_tick() call to only happen after a tick passed for the virtual cpu.

The patches cause nothing obvious to break, numbers from top look sane but I've seen something strange...

For a simple make -j6 workload top reports processes very often to be in state <defunct>. Thats' not terribly wrong since this can happens also without the patches but I wonder if this indicates that the scheduler behaves badly and does less often schedule the parent processes that gathers the waiting zombie processes?

Are there any indicators in the sched_debug output that I could look for?

Jan

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