[Mesa-dev] [PATCH 1/3] mesa/main: allow delayed initialization of performance monitors

[Nicolai Hähnle]

Most applications never use performance counters, so allow drivers to
skip potentially expensive initialization steps.

A driver that wants to use this must enable the appropriate extension(s)
at context initialization and set the InitPerfMonitorGroups driver function
which will be called the first time information about the performance monitor
groups is actually used.

The init_groups helper is called for API functions that can be called before
a monitor object exists. Functions that require an existing monitor object
can rely on init_groups having been called before.
---
 src/mesa/main/dd.h                  |  1 +
 src/mesa/main/performance_monitor.c | 39 +++++++++++++++++++++++++++++++++----
 2 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/src/mesa/main/dd.h b/src/mesa/main/dd.h
index 496a14f..e5281ce 100644
--- a/src/mesa/main/dd.h
+++ b/src/mesa/main/dd.h
@@ -727,6 +727,7 @@ struct dd_function_table {
     * \name Performance monitors
     */
    /*@{*/
+   void (*InitPerfMonitorGroups)(struct gl_context *ctx);
    struct gl_perf_monitor_object * (*NewPerfMonitor)(struct gl_context *ctx);
    void (*DeletePerfMonitor)(struct gl_context *ctx,
                              struct gl_perf_monitor_object *m);
diff --git a/src/mesa/main/performance_monitor.c b/src/mesa/main/performance_monitor.c
index 2d740da..98dfbea 100644
--- a/src/mesa/main/performance_monitor.c
+++ b/src/mesa/main/performance_monitor.c
@@ -53,6 +53,13 @@ _mesa_init_performance_monitors(struct gl_context *ctx)
    ctx->PerfMonitor.Groups = NULL;
 }
 
+static inline void
+init_groups(struct gl_context *ctx)
+{
+   if (unlikely(!ctx->PerfMonitor.Groups))
+      ctx->Driver.InitPerfMonitorGroups(ctx);
+}
+
 static struct gl_perf_monitor_object *
 new_performance_monitor(struct gl_context *ctx, GLuint index)
 {
@@ -171,6 +178,7 @@ _mesa_GetPerfMonitorGroupsAMD(GLint *numGroups, GLsizei groupsSize,
                               GLuint *groups)
 {
    GET_CURRENT_CONTEXT(ctx);
+   init_groups(ctx);
 
    if (numGroups != NULL)
       *numGroups = ctx->PerfMonitor.NumGroups;
@@ -191,7 +199,11 @@ _mesa_GetPerfMonitorCountersAMD(GLuint group, GLint *numCounters,
                                 GLsizei countersSize, GLuint *counters)
 {
    GET_CURRENT_CONTEXT(ctx);
-   const struct gl_perf_monitor_group *group_obj = get_group(ctx, group);
+   const struct gl_perf_monitor_group *group_obj;
+
+   init_groups(ctx);
+
+   group_obj = get_group(ctx, group);
    if (group_obj == NULL) {
       _mesa_error(ctx, GL_INVALID_VALUE,
                   "glGetPerfMonitorCountersAMD(invalid group)");
@@ -219,9 +231,11 @@ _mesa_GetPerfMonitorGroupStringAMD(GLuint group, GLsizei bufSize,
                                    GLsizei *length, GLchar *groupString)
 {
    GET_CURRENT_CONTEXT(ctx);
+   const struct gl_perf_monitor_group *group_obj;
 
-   const struct gl_perf_monitor_group *group_obj = get_group(ctx, group);
+   init_groups(ctx);
 
+   group_obj = get_group(ctx, group);
    if (group_obj == NULL) {
       _mesa_error(ctx, GL_INVALID_VALUE, "glGetPerfMonitorGroupStringAMD");
       return;
@@ -251,6 +265,8 @@ _mesa_GetPerfMonitorCounterStringAMD(GLuint group, GLuint counter,
    const struct gl_perf_monitor_group *group_obj;
    const struct gl_perf_monitor_counter *counter_obj;
 
+   init_groups(ctx);
+
    group_obj = get_group(ctx, group);
 
    if (group_obj == NULL) {
@@ -290,6 +306,8 @@ _mesa_GetPerfMonitorCounterInfoAMD(GLuint group, GLuint counter, GLenum pname,
    const struct gl_perf_monitor_group *group_obj;
    const struct gl_perf_monitor_counter *counter_obj;
 
+   init_groups(ctx);
+
    group_obj = get_group(ctx, group);
 
    if (group_obj == NULL) {
@@ -353,6 +371,8 @@ _mesa_GenPerfMonitorsAMD(GLsizei n, GLuint *monitors)
    if (MESA_VERBOSE & VERBOSE_API)
       _mesa_debug(ctx, "glGenPerfMonitorsAMD(%d)\n", n);
 
+   init_groups(ctx);
+
    if (n < 0) {
       _mesa_error(ctx, GL_INVALID_VALUE, "glGenPerfMonitorsAMD(n < 0)");
       return;
@@ -673,6 +693,8 @@ _mesa_GetFirstPerfQueryIdINTEL(GLuint *queryId)
    GET_CURRENT_CONTEXT(ctx);
    unsigned numGroups;
 
+   init_groups(ctx);
+
    /* The GL_INTEL_performance_query spec says:
     *
     *    "If queryId pointer is equal to 0, INVALID_VALUE error is generated."
@@ -705,6 +727,7 @@ extern void GLAPIENTRY
 _mesa_GetNextPerfQueryIdINTEL(GLuint queryId, GLuint *nextQueryId)
 {
    GET_CURRENT_CONTEXT(ctx);
+   init_groups(ctx);
 
    /* The GL_INTEL_performance_query spec says:
     *
@@ -744,6 +767,8 @@ _mesa_GetPerfQueryIdByNameINTEL(char *queryName, GLuint *queryId)
    GET_CURRENT_CONTEXT(ctx);
    unsigned i;
 
+   init_groups(ctx);
+
    /* The GL_INTEL_performance_query spec says:
     *
     *    "If queryName does not reference a valid query name, an INVALID_VALUE
@@ -783,9 +808,11 @@ _mesa_GetPerfQueryInfoINTEL(GLuint queryId,
    GET_CURRENT_CONTEXT(ctx);
    unsigned i;
 
-   const struct gl_perf_monitor_group *group_obj =
-      get_group(ctx, queryid_to_index(queryId));
+   const struct gl_perf_monitor_group *group_obj;
 
+   init_groups(ctx);
+
+   group_obj = get_group(ctx, queryid_to_index(queryId));
    if (group_obj == NULL) {
       /* The GL_INTEL_performance_query spec says:
        *
@@ -860,6 +887,8 @@ _mesa_GetPerfCounterInfoINTEL(GLuint queryId, GLuint counterId,
    unsigned counterIndex;
    unsigned i;
 
+   init_groups(ctx);
+
    group_obj = get_group(ctx, queryid_to_index(queryId));
 
    /* The GL_INTEL_performance_query spec says:
@@ -979,6 +1008,8 @@ _mesa_CreatePerfQueryINTEL(GLuint queryId, GLuint *queryHandle)
    struct gl_perf_monitor_object *m;
    unsigned i;
 
+   init_groups(ctx);
+
    /* This is not specified in the extension, but is the only sane thing to
     * do.
     */
-- 
2.5.0