On 08/12/15 01:42, Brian Paul wrote:
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. --- src/mesa/main/bufferobj.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++ src/mesa/main/mtypes.h | 4 ++++ 2 files changed, 59 insertions(+) diff --git a/src/mesa/main/bufferobj.c b/src/mesa/main/bufferobj.c index f985982..6bc1b5e 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 1eb1e21..de54169 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]; };
LGTM. Reviewed-by: Jose Fonseca <jfons...@vmware.com> _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
