Re: [PATCH] x86: Add --enable-rdtscp-in-benchtests

["H.J. Lu" <hjl dot tools at gmail dot com>]

On 10/23/18, Siddhesh Poyarekar <siddhesh@gotplt.org> wrote:
> On 23/10/18 2:34 PM, Florian Weimer wrote:
>> Shouldn't the benchtests use clock_gettime anyway, to avoid issues in
>> case the TSC is not synchronized across cores?
>
> There's an option USE_CLOCK_GETTIME to make benchtests do that, but
> otherwise it uses the hp_timing bits by default.

I want something better that rdtsc and very low overhead since some bench
tests only last a few cycles.  Adding lfence may make timing data look like
noise.


-- 
H.J.