time: add Ticker.Reset

This CL implements Ticker.Reset method in time package.

Benchmark:
name                 time/op
TickerReset-12       6.41µs ±10%
TickerResetNaive-12  95.7µs ±12%

Fixes #33184

Change-Id: I12c651f81e452541bcbbc748b45f038aae1f8dae
Reviewed-on: https://go-review.googlesource.com/c/go/+/217362
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/src/runtime/time.go b/src/runtime/time.go
index af5db4cc58..9e1129537a 100644
--- a/src/runtime/time.go
+++ b/src/runtime/time.go
@@ -233,6 +233,12 @@ func resetTimer(t *timer, when int64) {
 	resettimer(t, when)
 }
 
+// modTimer modifies an existing timer.
+//go:linkname modTimer time.modTimer
+func modTimer(t *timer, when, period int64, f func(interface{}, uintptr), arg interface{}, seq uintptr) {
+	modtimer(t, when, period, f, arg, seq)
+}
+
 // Go runtime.
 
 // Ready the goroutine arg.
@@ -402,7 +408,7 @@ func dodeltimer0(pp *p) bool {
 }
 
 // modtimer modifies an existing timer.
-// This is called by the netpoll code.
+// This is called by the netpoll code or time.Ticker.Reset.
 func modtimer(t *timer, when, period int64, f func(interface{}, uintptr), arg interface{}, seq uintptr) {
 	if when < 0 {
 		when = maxWhen