How to get better precision out of getrusage on the ARM?

Russell King - ARM Linux linux at arm.linux.org.uk
Tue Dec 22 06:49:07 PST 2015


On Tue, Dec 22, 2015 at 09:30:30AM -0500, Patrick Doyle wrote:
> Short version:
> My application running on a Cortex-A5 processor (the SAMA5D2 from
> Atmel) calls getrusage(RUSAGE_THREAD, ...), which returns cpu time
> quantized to the kernel tick frequency (100Hz or 1Khz, depending on
> CONFIG_HZ_100 vs CONFIG_HZ_1000).
> 
> How can I get better precision for sched_clock on the (Cortex-A5) ARM?
>  The x86 uses the TSC.

You need to provide a sched_clock() implementation using
sched_clock_register().

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