| // Copyright 2023 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // Tests increasing and decreasing GOMAXPROCS to try and |
| // catch issues with stale proc state. |
| |
| //go:build ignore |
| |
| package main |
| |
| import ( |
| "log" |
| "os" |
| "runtime" |
| "runtime/trace" |
| "time" |
| ) |
| |
| func main() { |
| // Start a goroutine that calls runtime.GC to try and |
| // introduce some interesting events in between the |
| // GOMAXPROCS calls. |
| go func() { |
| for { |
| runtime.GC() |
| time.Sleep(1 * time.Millisecond) |
| } |
| }() |
| |
| // Start tracing. |
| if err := trace.Start(os.Stdout); err != nil { |
| log.Fatalf("failed to start tracing: %v", err) |
| } |
| // Run GOMAXPROCS a bunch of times, up and down. |
| for i := 1; i <= 16; i *= 2 { |
| runtime.GOMAXPROCS(i) |
| time.Sleep(1 * time.Millisecond) |
| } |
| for i := 16; i >= 1; i /= 2 { |
| runtime.GOMAXPROCS(i) |
| time.Sleep(1 * time.Millisecond) |
| } |
| // Stop tracing. |
| trace.Stop() |
| } |