t.Sub(u) would be -20 milliseconds.
The right computation is u.Sub(t), but rewrite to be even clearer.
Thanks to Karsten Weiss for catching this.
Change-Id: I6e274d69b0301840d57c5c65bf4114da0d33bf10
Reviewed-on: https://go-review.googlesource.com/46971
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
// approximately 20 milliseconds, even if the wall clock is changed during
// the operation being timed:
//
-// t := time.Now()
+// start := time.Now()
// ... operation that takes 20 milliseconds ...
-// u := time.Now()
-// elapsed := t.Sub(u)
+// t := time.Now()
+// elapsed := t.Sub(start)
//
// Other idioms, such as time.Since(start), time.Until(deadline), and
// time.Now().Before(deadline), are similarly robust against wall clock