Cycles: Add artificial memory limit debug option for OpenCL

intern/cycles/blender/addon/properties.py

@@ -703,6 +703,9 @@ class CyclesRenderSettings(bpy.types.PropertyGroup):
 
         cls.debug_use_opencl_debug = BoolProperty(name="Debug OpenCL", default=False)
 
+        cls.debug_opencl_mem_limit = IntProperty(name="Memory limit", default=0,
+            description="Artificial limit on OpenCL memory usage in MB (0 to disable limit)")
+
     @classmethod
     def unregister(cls):
         del bpy.types.Scene.cycles

intern/cycles/blender/addon/ui.py

@@ -1608,6 +1608,7 @@ class CyclesRender_PT_debug(CyclesButtonsPanel, Panel):
         col.prop(cscene, "debug_opencl_device_type", text="Device")
         col.prop(cscene, "debug_opencl_kernel_single_program", text="Single Program")
         col.prop(cscene, "debug_use_opencl_debug", text="Debug")
+        col.prop(cscene, "debug_opencl_mem_limit")
 
 
 class CyclesParticle_PT_CurveSettings(CyclesButtonsPanel, Panel):

intern/cycles/blender/blender_python.cpp

@@ -106,6 +106,7 @@ bool debug_flags_sync_from_scene(BL::Scene b_scene)
 	}
 	/* Synchronize other OpenCL flags. */
 	flags.opencl.debug = get_boolean(cscene, "debug_use_opencl_debug");
+	flags.opencl.mem_limit = ((size_t)get_int(cscene, "debug_opencl_mem_limit"))*1024*1024;
 	flags.opencl.single_program = get_boolean(cscene, "debug_opencl_kernel_single_program");
 	return flags.opencl.device_type != opencl_device_type ||
 	       flags.opencl.kernel_type != opencl_kernel_type;

intern/cycles/device/opencl/opencl_base.cpp

@@ -20,6 +20,7 @@
 
 #include "kernel/kernel_types.h"
 
+#include "util/util_algorithm.h"
 #include "util/util_foreach.h"
 #include "util/util_logging.h"
 #include "util/util_md5.h"
@@ -280,6 +281,10 @@ void OpenCLDeviceBase::mem_alloc(const char *name, device_memory& mem, MemoryTyp
 	cl_ulong max_alloc_size = 0;
 	clGetDeviceInfo(cdDevice, CL_DEVICE_MAX_MEM_ALLOC_SIZE, sizeof(cl_ulong), &max_alloc_size, NULL);
 
+	if(DebugFlags().opencl.mem_limit) {
+		max_alloc_size = min(max_alloc_size, DebugFlags().opencl.mem_limit - stats.mem_used);
+	}
+
 	if(size > max_alloc_size) {
 		string error = "Scene too complex to fit in available memory.";
 		if(name != NULL) {

intern/cycles/device/opencl/opencl_split.cpp

@@ -25,6 +25,7 @@
 
 #include "device/device_split_kernel.h"
 
+#include "util/util_algorithm.h"
 #include "util/util_logging.h"
 #include "util/util_md5.h"
 #include "util/util_path.h"
@@ -423,6 +424,11 @@ public:
 
 		cl_ulong max_buffer_size;
 		clGetDeviceInfo(device->cdDevice, CL_DEVICE_MAX_MEM_ALLOC_SIZE, sizeof(cl_ulong), &max_buffer_size, NULL);
+
+		if(DebugFlags().opencl.mem_limit) {
+			max_buffer_size = min(max_buffer_size, DebugFlags().opencl.mem_limit - device->stats.mem_used);
+		}
+
 		VLOG(1) << "Maximum device allocation size: "
 		        << string_human_readable_number(max_buffer_size) << " bytes. ("
 		        << string_human_readable_size(max_buffer_size) << ").";

intern/cycles/util/util_debug.cpp

@@ -184,8 +184,8 @@ std::ostream& operator <<(std::ostream &os,
 	   << "  Device type    : " << opencl_device_type << "\n"
 	   << "  Kernel type    : " << opencl_kernel_type << "\n"
 	   << "  Debug          : " << string_from_bool(debug_flags.opencl.debug) << "\n"
-	   << "  Single program : " << string_from_bool(debug_flags.opencl.single_program)
-	   << "\n";
+	   << "  Single program : " << string_from_bool(debug_flags.opencl.single_program) << "\n"
+	   << "  Memory limit   : " << string_human_readable_size(debug_flags.opencl.mem_limit) << "\n";
 	return os;
 }
 

intern/cycles/util/util_debug.h

@@ -115,6 +115,10 @@ public:
 
 		/* Use single program */
 		bool single_program;
+
+		/* TODO(mai): Currently this is only for OpenCL, but we should have it implemented for all devices. */
+		/* Artificial memory limit in bytes (0 if disabled). */
+		size_t mem_limit;
 	};
 
 	/* Get instance of debug flags registry. */