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authorBrian Paul <[email protected]>2015-12-07 18:38:03 -0700
committerBrian Paul <[email protected]>2015-12-09 09:43:47 -0700
commitab0651ccfd8c8c4bca26a106225e188fe965d8d0 (patch)
tree3e781c4c6be78f0aa9353c956e47649da7531d44
parent7d3df58125671bef354f97577c3b50f5b858a42d (diff)
mesa: detect inefficient buffer use and report through debug output
When a buffer is created with GL_STATIC_DRAW, its contents should not be changed frequently. But that's exactly what one application I'm debugging does. This patch adds code to try to detect inefficient buffer use in a couple places. The GL_ARB_debug_output mechanism is used to report the issue. NVIDIA's driver detects these sort of things too. Other types of inefficient buffer use could also be detected in the future. Reviewed-by: José Fonseca <[email protected]>
-rw-r--r--src/mesa/main/bufferobj.c55
-rw-r--r--src/mesa/main/mtypes.h4
2 files changed, 59 insertions, 0 deletions
diff --git a/src/mesa/main/bufferobj.c b/src/mesa/main/bufferobj.c
index f985982c801..6bc1b5ea9d1 100644
--- a/src/mesa/main/bufferobj.c
+++ b/src/mesa/main/bufferobj.c
@@ -51,6 +51,34 @@
/**
+ * We count the number of buffer modification calls to check for
+ * inefficient buffer use. This is the number of such calls before we
+ * issue a warning.
+ */
+#define BUFFER_WARNING_CALL_COUNT 4
+
+
+/**
+ * Helper to warn of possible performance issues, such as frequently
+ * updating a buffer created with GL_STATIC_DRAW.
+ */
+static void
+buffer_usage_warning(struct gl_context *ctx, const char *fmt, ...)
+{
+ va_list args;
+ GLuint msg_id = 0;
+
+ va_start(args, fmt);
+ _mesa_gl_vdebug(ctx, &msg_id,
+ MESA_DEBUG_SOURCE_API,
+ MESA_DEBUG_TYPE_PERFORMANCE,
+ MESA_DEBUG_SEVERITY_MEDIUM,
+ fmt, args);
+ va_end(args);
+}
+
+
+/**
* Used as a placeholder for buffer objects between glGenBuffers() and
* glBindBuffer() so that glIsBuffer() can work correctly.
*/
@@ -1677,6 +1705,21 @@ _mesa_buffer_sub_data(struct gl_context *ctx, struct gl_buffer_object *bufObj,
if (size == 0)
return;
+ bufObj->NumSubDataCalls++;
+
+ if ((bufObj->Usage == GL_STATIC_DRAW ||
+ bufObj->Usage == GL_STATIC_COPY) &&
+ bufObj->NumSubDataCalls >= BUFFER_WARNING_CALL_COUNT) {
+ /* If the application declared the buffer as static draw/copy or stream
+ * draw, it should not be frequently modified with glBufferSubData.
+ */
+ buffer_usage_warning(ctx,
+ "using %s(buffer %u, offset %u, size %u) to "
+ "update a %s buffer",
+ func, bufObj->Name, offset, size,
+ _mesa_enum_to_string(bufObj->Usage));
+ }
+
bufObj->Written = GL_TRUE;
assert(ctx->Driver.BufferSubData);
@@ -2384,6 +2427,18 @@ _mesa_map_buffer_range(struct gl_context *ctx,
return NULL;
}
+ if (access & GL_MAP_WRITE_BIT) {
+ bufObj->NumMapBufferWriteCalls++;
+ if ((bufObj->Usage == GL_STATIC_DRAW ||
+ bufObj->Usage == GL_STATIC_COPY) &&
+ bufObj->NumMapBufferWriteCalls >= BUFFER_WARNING_CALL_COUNT) {
+ buffer_usage_warning(ctx,
+ "using %s(buffer %u, offset %u, length %u) to "
+ "update a %s buffer",
+ func, bufObj->Name, offset, length,
+ _mesa_enum_to_string(bufObj->Usage));
+ }
+ }
assert(ctx->Driver.MapBufferRange);
map = ctx->Driver.MapBufferRange(ctx, offset, length, access, bufObj,
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 1eb1e21edeb..de54169cc8a 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -1275,6 +1275,10 @@ struct gl_buffer_object
GLboolean Immutable; /**< GL_ARB_buffer_storage */
gl_buffer_usage UsageHistory; /**< How has this buffer been used so far? */
+ /** Counters used for buffer usage warnings */
+ GLuint NumSubDataCalls;
+ GLuint NumMapBufferWriteCalls;
+
struct gl_buffer_mapping Mappings[MAP_COUNT];
};