Hi Eric,
On Mon, Jun 19, 2023 at 10:00:11PM +0200, Eric Auger wrote:
> Hi,
>
> On 6/16/23 13:52, Alexandru Elisei wrote:
> > Hi,
> >
> > The test looks much more readable now, some comments below.
> >
> > On Wed, May 31, 2023 at 10:14:37PM +0200, Eric Auger wrote:
> >> [..]
> >> +static void test_mem_access_reliability(bool overflow_at_64bits)
> >> +{
> >> + uint32_t events[] = {MEM_ACCESS};
> >> + void *addr = malloc(PAGE_SIZE);
> >> + uint64_t count, delta, max = 0, min = pmevcntr_mask();
> >> + uint64_t pre_overflow2 = PRE_OVERFLOW2(overflow_at_64bits);
> >> + uint64_t pmcr_lp = overflow_at_64bits ? PMU_PMCR_LP : 0;
> >> + bool overflow = false;
> >> +
> >> + if (!satisfy_prerequisites(events, ARRAY_SIZE(events)) ||
> >> + !check_overflow_prerequisites(overflow_at_64bits))
> >> + return;
> >> +
> >> + pmu_reset();
> >> + write_regn_el0(pmevtyper, 0, MEM_ACCESS | PMEVTYPER_EXCLUDE_EL0);
> >> + for (int i = 0; i < 100; i++) {
> >> + pmu_reset();
> >> + write_regn_el0(pmevcntr, 0, pre_overflow2);
> >> + write_sysreg_s(0x1, PMCNTENSET_EL0);
> >> + isb();
> >> + mem_access_loop(addr, COUNT, pmu.pmcr_ro | PMU_PMCR_E | pmcr_lp);
> >> + count = read_regn_el0(pmevcntr, 0);
> >> + if (count >= pre_overflow2) {
> >> + /* not counter overflow, as expected */
> >> + delta = count - pre_overflow2;
> > Personally, I find the names confusing. Since the test tries to see how
> > much the counting is unreliable, I would have have expected delta to be
> > difference between the expected number of events incremented (i.e., COUNT)
> > and the actual number of events recorded in the counter. I would rename
> > count to cntr_val and delta to num_events, but that might be just personal
> > bias and I leave it up to you if think this might be useful.
> I followed your suggestion
Sorry for that, I guess I didn't think things through :(
Thanks,
Alex
