Currently pmu.c sets num_counters to MIN(num_gp_counters, num_gp_events).
This is to prevent the out-of-bound access to gp_events[] array in
check_counters_many(). However it also means that check_counters_many()
can NOT stress all gp counters if num_gp_counters > num_gp_events. This
small patch changes the value of num_counters back to num_gp_counters and
prevents the out-of-bound problem by using the mod function in the array
access.
Signed-off-by: Wei Huang <wei@xxxxxxxxxx>
---
x86/pmu.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/x86/pmu.c b/x86/pmu.c
index a0238dc..b56b61e 100644
--- a/x86/pmu.c
+++ b/x86/pmu.c
@@ -275,7 +275,8 @@ static void check_counters_many(void)
cnt[n].count = 0;
cnt[n].ctr = MSR_IA32_PERFCTR0 + n;
- cnt[n].config = EVNTSEL_OS | EVNTSEL_USR | gp_events[i].unit_sel;
+ cnt[n].config = EVNTSEL_OS | EVNTSEL_USR |
+ gp_events[i % ARRAY_SIZE(gp_events)].unit_sel;
n++;
}
for (i = 0; i < edx.split.num_counters_fixed; i++) {
@@ -397,8 +398,6 @@ int main(int ac, char **av)
printf("Fixed counter width: %d\n", edx.split.bit_width_fixed);
num_counters = eax.split.num_counters;
- if (num_counters > ARRAY_SIZE(gp_events))
- num_counters = ARRAY_SIZE(gp_events);
apic_write(APIC_LVTPC, PC_VECTOR);
--
2.7.5
