Error out of counter splitting if group max is zero (#70)

* Error out of counter splitting if group max is zero

A counter group having a counter max of zero is invalid and
will ultimately result in a hang when we try to split counters
into multiple passes. This is one of various scenarios that
result in a hang during counter splitting; see

 #69

This fixes only that specific scenario. We now check that the
group max isn't zero, and if it is, we give up trying to split
a public counter's HW counters into multiple passes. We log
an error, too.

Again, this isn't a comprehensive fix for issue 69. There could
be other cases of bad data that result in a hang. Issue 69 should
be fixed with a pass cap limit to cover all cases. But this
commit still adds value in that it flags the specific invalid GPU
counter metadata in addition to avoiding the hang.

Change-Id: I56d7d2043ba92c1b6088f0fdd68f5ec844e7b823

include/gpu_performance_api/gpu_perf_api_types.h

@@ -170,7 +170,8 @@ typedef enum
     kGpaStatusErrorLibAlreadyLoaded                 = -41,
     kGpaStatusErrorOtherSessionActive               = -42,
     kGpaStatusErrorException                        = -43,
-    kGpaStatusMin                                   = kGpaStatusErrorException,
+    kGpaStatusErrorInvalidCounterGroupData          = -44,
+    kGpaStatusMin                                   = kGpaStatusErrorInvalidCounterGroupData,
     kGpaStatusInternal                              = 256,  ///< Status codes used internally within GPUPerfAPI.
 } GpaStatus;
 

source/gpu_perf_api_common/gpu_perf_api.cc

@@ -1659,7 +1659,8 @@ static const char* kErrorString[] = {
     GPA_ENUM_STRING_VAL(kGpaStatusErrorTimeout, "GPA Error: Attempt to Retrieve Data Failed due to Timeout."),
     GPA_ENUM_STRING_VAL(kGpaStatusErrorLibAlreadyLoaded, "GPA Error: Library Is Already Loaded."),
     GPA_ENUM_STRING_VAL(kGpaStatusErrorOtherSessionActive, "GPA Error: Other Session Is Active."),
-    GPA_ENUM_STRING_VAL(kGpaStatusErrorException, "GPA Error: Exception Occurred.")};
+    GPA_ENUM_STRING_VAL(kGpaStatusErrorException, "GPA Error: Exception Occurred."),
+    GPA_ENUM_STRING_VAL(kGpaStatusErrorInvalidCounterGroupData, "GPA Error: Counter group data is invalid.")};
 
 /// Size of kErrorString array.
 static size_t kErrorStringSize = sizeof(kErrorString) / sizeof(const char*);

source/gpu_perf_api_counter_generator/gpa_counter_scheduler_base.cc

@@ -273,13 +273,25 @@ GpaStatus GpaCounterSchedulerBase::GetNumRequiredPasses(GpaUInt32* num_required_
     // Add the HW groups max's.
     for (unsigned int i = 0; i < hw_counters->internal_counter_groups_.size(); ++i)
     {
-        max_counters_per_group.push_back(hw_counters->internal_counter_groups_[i].max_active_discrete_counters);
+        auto count = hw_counters->internal_counter_groups_[i].max_active_discrete_counters;
+        if (count == 0)
+        {
+            GPA_LOG_DEBUG_ERROR("Hardware counter group '%s' has zero for max-counters-per-group.", hw_counters->internal_counter_groups_[i].name);
+            return kGpaStatusErrorInvalidCounterGroupData;
+        }
+        max_counters_per_group.push_back(count);
     }
 
     // Add the Additional groups max's.
     for (unsigned int i = 0; i < hw_counters->additional_group_count_; ++i)
     {
-        max_counters_per_group.push_back(hw_counters->additional_groups_[i].max_active_discrete_counters);
+        auto count = hw_counters->additional_groups_[i].max_active_discrete_counters;
+        if (count == 0)
+        {
+            GPA_LOG_DEBUG_ERROR("Hardware counter additional group '%s' has zero for max-counters-per-group.", hw_counters->additional_groups_[i].name);
+            return kGpaStatusErrorInvalidCounterGroupData;
+        }
+        max_counters_per_group.push_back(count);
     }
 
     GpaCounterGroupAccessor accessor(hw_counters->internal_counter_groups_,

source/gpu_perf_api_counter_generator/gpa_split_counters_interfaces.h

@@ -16,10 +16,10 @@
 
 #ifdef DEBUG_PUBLIC_COUNTER_SPLITTER
 #include <sstream>
-#include "gpu_perf_api_common/logging.h"
 #endif
 
 #include "gpu_perf_api_counter_generator/gpa_derived_counter.h"
+#include "gpu_perf_api_common/logging.h"
 
 /// @brief Enum to represent the different SQ shader stages.
 enum GpaSqShaderStage
@@ -378,6 +378,11 @@ class IGpaSplitCounters
         }
 
         unsigned int group_limit = max_counters_per_group[group_index];
+        if (group_limit == 0)
+        {
+            GPA_LOG_DEBUG_ERROR("Group(%d) counter limit is zero.", group_index);
+            return false;
+        }
 
         // This should never occur. It indicates the counter relies on a block without any collectible events.
         assert(group_limit > 0);