[Mesa-dev] [PATCH 2/2] mesa: don't double incr/decr ActiveCounters

[Brian Paul]

On 07/02/2018 09:13 AM, Rob Clark wrote:
> Frameretrace ends up w/ excess calls to SelectPerfMonitorCountersAMD()
> which ends up re-enabling already enabled counters.  Which causes
> ActiveCounters[group] to be double incremented for the same counter.
> This causes BeginPerfMonitorAMD() to fail.
> 
> The AMD_performance_monitor spec doesn't say that an error should be
> generated in this case.  So I think the safe thing to do is just safe-
> guard against excess increments/decrements.
> 
> Signed-off-by: Rob Clark <robdclark at gmail.com>
> ---
>   src/mesa/main/performance_monitor.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/src/mesa/main/performance_monitor.c b/src/mesa/main/performance_monitor.c
> index 359727777ff..37762e056b0 100644
> --- a/src/mesa/main/performance_monitor.c
> +++ b/src/mesa/main/performance_monitor.c
> @@ -480,12 +480,16 @@ _mesa_SelectPerfMonitorCountersAMD(GLuint monitor, GLboolean enable,
>      if (enable) {
>         /* Enable the counters */
>         for (i = 0; i < numCounters; i++) {
> +         if (BITSET_TEST(m->ActiveCounters[group], counterList[i]))
> +            continue;
>            ++m->ActiveGroups[group];
>            BITSET_SET(m->ActiveCounters[group], counterList[i]);

If it were me, I'd simply use a conditional w/out continue:

    if (!BITSET_TEST(m->ActiveCounters[group], counterList[i])) {
       ++m->ActiveGroups[group];
       BITSET_SET(m->ActiveCounters[group], counterList[i]);
    }

>         }
>      } else {
>         /* Disable the counters */
>         for (i = 0; i < numCounters; i++) {
> +         if (!BITSET_TEST(m->ActiveCounters[group], counterList[i]))
> +            continue;
>            --m->ActiveGroups[group];
>            BITSET_CLEAR(m->ActiveCounters[group], counterList[i]);
>         }
> 

-Brian