Querying the thread clock takes the overwhelming majority of time when using the VM-internal recorders (ring, startup, endless, file). Including the thread clocks in the timeline allowed visualizing roughly how much an event got scheduled out, but not when. This is a high price to pay for such fuzzy information. Precise scheduling information is available from Fuchsia tracing, systrace or Signposts.
```
import "dart:developer";
main() {
var n = 1000000;
var watch = new Stopwatch()..start();
for (var i = 0; i < n; i++) {
Timeline.timeSync("EventName", () {});
}
print("${watch.elapsedMicroseconds.toDouble() / n} us/event");
}
```
--timeline_recorder=ring 2.751822 -> 0.487936 us/event (5.64x)
--timeline_recorder=systrace 0.440439 -> 0.435997 us/event
TEST=ci
Bug: https://github.com/flutter/flutter/issues/121372
Change-Id: Ib6d625f28384a4e87df2a3305483f0f6facd08ff
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/286661
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Ben Konyi <bkonyi@google.com>
Reviewed-by: Siva Annamalai <asiva@google.com>
Ryan Macnak
08634ec4ee