ARM public key benchmark
tg at gmplib.org
Thu Apr 4 14:44:27 CEST 2013
Richard Henderson <rth at twiddle.net> writes:
On 2013-04-04 06:51, Niels Möller wrote:
> And it's no use to even think of porting the loop mixer to arm without
> access to cycle-accurate timing.
Looking around the web it seems that what most folks do is write a
minimal kernel module that toggles the bit that allows userspace
access to the cycle counter MSRs. They're generally supervisor only
because then userspace *could* set up cycle counter timer interrupts.
I havn't fiddled with this myself, because the A15 includes a real
high-resolution clock, which is accessed via CLOCK_MONOTONIC.
But it might be worth adding some code that looks for the MSR. Just
set up a SIGILL handler and try the read.
I tried these kernel modules, in fact I bravely tried several suggested
variants. Not of them made cycle counters be accessible on my systems
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