[PATCH 6/6] aarch64: Add hp-timing.h

[pinskia@gmail.com]

> On Jul 21, 2014, at 4:41 AM, Andreas Schwab <schwab@suse.de> wrote:
> 
> Richard Henderson <rth@twiddle.net> writes:
> 
>> +/* Sync the instruction stream, and read from the virtual cycle counter.  */
>> +#define HP_TIMING_NOW(Var) \
>> +  __asm__ __volatile__ ("isb; mrs %0, cntvct_el0" : "=r" (Var))
> 
> According to https://bugs.launchpad.net/bugs/1344320 the generic timers
> are not part of the kernel-to-userspace contract.


I think this is bogus for the kernel folks not allow a high precision timer in user space. Timers like this are needed for micro-benchmarking compiler changes along with other libc changes. 

Thanks,
Andrew

> 
> Andreas.
> 
> -- 
> Andreas Schwab, SUSE Labs, schwab@suse.de
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