Add tracing entry points in the rendering pipelineupstream/galinelle_mbgl_tracing

This also includes a default tracing implementation that does not require
hooking into a platform instrumentation, but simply stores timestamps
into an array that can be dumped into a json file.

Among possible use cases, dumping such metrics to file in CI to detect
regressions of specific stages of the pipeline.

1 files changed, 5 insertions, 0 deletions

diff --git a/include/mbgl/util/chrono.hpp b/include/mbgl/util/chrono.hpp
index 723cd131e3..2b16e74b32 100644
--- a/include/mbgl/util/chrono.hpp
+++ b/include/mbgl/util/chrono.hpp
@@ -9,6 +9,7 @@ using Clock = std::chrono::steady_clock;
 
 using Seconds = std::chrono::seconds;
 using Milliseconds = std::chrono::milliseconds;
+using Nanoseconds = std::chrono::nanoseconds;
 
 using TimePoint = Clock::time_point;
 using Duration  = Clock::duration;
@@ -22,6 +23,10 @@ inline Timestamp now() {
     return std::chrono::time_point_cast<Seconds>(std::chrono::system_clock::now());
 }
 
+inline uint64_t now_ns() {
+    return Clock::now().time_since_epoch().count();
+}
+
 // Returns the RFC1123 formatted date. E.g. "Tue, 04 Nov 2014 02:13:24 GMT"
 std::string rfc1123(Timestamp);