| // 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 a GC-heavy program. This is useful for shaking out |
| // all sorts of corner cases about GC-related ranges. |
| |
| //go:build ignore |
| |
| package main |
| |
| import ( |
| "log" |
| "os" |
| "runtime" |
| "runtime/trace" |
| "time" |
| ) |
| |
| type node struct { |
| children [4]*node |
| data [128]byte |
| } |
| |
| func makeTree(depth int) *node { |
| if depth == 0 { |
| return new(node) |
| } |
| return &node{ |
| children: [4]*node{ |
| makeTree(depth - 1), |
| makeTree(depth - 1), |
| makeTree(depth - 1), |
| makeTree(depth - 1), |
| }, |
| } |
| } |
| |
| var trees [16]*node |
| var ballast *[16]*[1024]*node |
| var sink [][]byte |
| |
| func main() { |
| for i := range trees { |
| trees[i] = makeTree(6) |
| } |
| ballast = new([16]*[1024]*node) |
| for i := range ballast { |
| ballast[i] = new([1024]*node) |
| for j := range ballast[i] { |
| ballast[i][j] = &node{ |
| data: [128]byte{1, 2, 3, 4}, |
| } |
| } |
| } |
| |
| procs := runtime.GOMAXPROCS(-1) |
| sink = make([][]byte, procs) |
| |
| for i := 0; i < procs; i++ { |
| i := i |
| go func() { |
| for { |
| sink[i] = make([]byte, 4<<10) |
| } |
| }() |
| } |
| // Increase the chance that we end up starting and stopping |
| // mid-GC by only starting to trace after a few milliseconds. |
| time.Sleep(5 * time.Millisecond) |
| |
| // Start tracing. |
| if err := trace.Start(os.Stdout); err != nil { |
| log.Fatalf("failed to start tracing: %v", err) |
| } |
| defer trace.Stop() |
| |
| // Let the tracing happen for a bit. |
| time.Sleep(400 * time.Millisecond) |
| } |