sched_clock: Provide local_clock() and improve documentation
in [Kernel]
|
Prev: Quickstart Button ACPI driver to serve PNP0C32 ACPI devices
Next: sched_clock: Provide local_clock() and improve documentation
From: Chad Talbott on 28 May 2010 14:20 On Fri, May 28, 2010 at 6:13 AM, Peter Zijlstra <peterz(a)infradead.org> wrote: > + * local_clock() � � �-- is cpu_clock() on the current cpu. Pretty sure this should read, "is cpu_clock() on *some* cpu," since there is no guarantee in a preemptible kernel that local_clock() returns on the same CPU that it was called from. The caller has to do the preempt protection itself. The function could be written as follows (thanks Salman Qazi): u64 local_clock(unsigned int *where) { u64 clock; unsigned long flags; local_irq_save(flags); *where = smp_processor_id(); clock = sched_clock_cpu(*where); local_irq_restore(flags); return clock; } but I don't see the utility of the resulting routine. Chad -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |