Messages in this thread | | | Date | Wed, 2 Oct 2013 13:14:44 -0400 | From | Santosh Shilimkar <> | Subject | Re: [PATCH] sched_clock: fix postinit no sched_clock function check |
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On Wednesday 02 October 2013 01:09 PM, Will Deacon wrote: > On Wed, Oct 02, 2013 at 05:55:28PM +0100, Santosh Shilimkar wrote: >> The sched_clock code uses 2 levels of function pointers, sched_clock_func() >> and read_sched_clock() but the no sched_clock check in postinit() just >> checks read_sched_clock(). >> >> This leads to kernel falling back to jiffy based sched clock even in >> presence of sched_clock_func() which is not desirable. >> >> Fix the postinit() check to avoid the issue. Probably the issue is hidden >> so far on most of the arm SOCs because of already existing sched_clock >> registrations apart from arch_timer sched_clock. One can reproduce the >> issue by just have arch_timer as sched_clock > > Isn't this just an issue with the arch timer driver not calling > setup_sched_clock? Instead, we munge around with sched_clock_func directly, > which doesn't appear to be the way anybody else deals with this. > I thought about that option as well but was not sure since even in that case the check is not complete. We just ensure that function is popullated.
> I'm not sure of the history though, so perhaps there's a reason for this... > Am curious as well.
Regards, Santosh
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