vo_opengl: refactor vo performance subsystem

This replaces `vo-performance` by `vo-passes`, bringing with it a number
of changes and improvements:

1. mpv users can now introspect the vo_opengl passes, which is something
   that has been requested multiple times.

2. performance data is now measured per-pass, which helps both
   development and debugging.

3. since adding more passes is cheap, we can now report information for
   more passes (e.g. the blit pass, and the osd pass). Note: we also
   switch to nanosecond scale, to be able to measure these passes
   better.

4. `--user-shaders` authors can now describe their own passes, helping
   users both identify which user shaders are active at any given time
   as well as helping shader authors identify performance issues.

5. the timing data per pass is now exported as a full list of samples,
   so projects like Argon-/mpv-stats can immediately read out all of the
   samples and render a graph without having to manually poll this
   option constantly.

Due to gl_timer's design being complicated (directly reading performance
data would block, so we delay the actual read-back until the next _start
command), it's vital not to conflate different passes that might be
doing different things from one frame to another. To accomplish this,
the actual timers are stored as part of the gl_shader_cache's sc_entry,
which makes them unique for that exact shader.

Starting and stopping the time measurement is easy to unify with the
gl_sc architecture, because the existing API already relies on a
"generate, render, reset" flow, so we can just put timer_start and
timer_stop in sc_generate and sc_reset, respectively.

The ugliest thing about this code is that due to the need to keep pass
information relatively stable in between frames, we need to distinguish
between "new" and "redrawn" frames, which bloats the code somewhat and
also feels hacky and vo_opengl-specific. (But then again, this entire
thing is vo_opengl-specific)

1 files changed, 21 insertions, 3 deletions

diff --git a/video/out/vo.h b/video/out/vo.h
index c59e1b04c8..6dce8f6c2f 100644
--- a/video/out/vo.h
+++ b/video/out/vo.h
@@ -143,13 +143,31 @@ struct voctrl_playback_state {
 };
 
 // VOCTRL_PERFORMANCE_DATA
-struct voctrl_performance_entry {
-    // Times are in microseconds
+#define PERF_SAMPLE_COUNT 256u
+
+struct mp_pass_perf {
+    // times are all in nanoseconds
     uint64_t last, avg, peak;
+    // this is a ring buffer, indices are relative to index and modulo
+    // PERF_SAMPLE_COUNT
+    uint64_t *samples;
+    int count;
+    int index;
+};
+
+#define VO_PASS_PERF_MAX 128
+
+struct mp_frame_perf {
+    int count;
+    struct mp_pass_perf perf[VO_PASS_PERF_MAX];
+    // The owner of this struct does not have ownership over the names, and
+    // they may change at any time - so this struct should not be stored
+    // anywhere or the results reused
+    char *desc[VO_PASS_PERF_MAX];
 };
 
 struct voctrl_performance_data {
-    struct voctrl_performance_entry upload, render, present;
+    struct mp_frame_perf fresh, redraw;
 };
 
 enum {