[botan-devel] Set the cpu speed in the environment or command line for ./botan speed

Jack Lloyd jack at randombit.net
Thu Mar 8 05:41:44 EST 2018

On Wed, Mar 07, 2018 at 08:13:33PM -0500, Jeffrey Walton wrote:
> Hi Everyone,
> I'm looking for a way to set the cpu speed in the environment or from
> the command line when running ./botan speed.

This doesn't exist in 2.4 but in master (upcoming 2.5) you can use the
option --cpu-clock-ratio which expresses a ratio between the measured
CPU clocks and the actual CPU clocks. This was added for POWER8 which
has a fixed 512 MHz timebase, regardless of what the processor is
running at. So for example on a 3.0 GHz POWER8 you would use
--cpu-clock-ratio=.17 (.17 ~ 512/3000) so that CPU clocks are reported

Worth mentioning we don't have any code for getting the cycle counter
on ARM or MIPS so for IoT this will not be useful anyway.


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