annotations-stress.go

Documentation: internal/trace/testdata/testprog

     1  // Copyright 2023 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Tests user tasks, regions, and logging.
     6  
     7  //go:build ignore
     8  
     9  package main
    10  
    11  import (
    12  	"context"
    13  	"fmt"
    14  	"log"
    15  	"os"
    16  	"runtime/trace"
    17  	"time"
    18  )
    19  
    20  func main() {
    21  	baseCtx := context.Background()
    22  
    23  	// Create a task that starts and ends entirely outside of the trace.
    24  	ctx0, t0 := trace.NewTask(baseCtx, "parent")
    25  
    26  	// Create a task that starts before the trace and ends during the trace.
    27  	ctx1, t1 := trace.NewTask(ctx0, "type1")
    28  
    29  	// Start tracing.
    30  	if err := trace.Start(os.Stdout); err != nil {
    31  		log.Fatalf("failed to start tracing: %v", err)
    32  	}
    33  	t1.End()
    34  
    35  	// Create a task that starts during the trace and ends after.
    36  	ctx2, t2 := trace.NewTask(ctx0, "type2")
    37  
    38  	// Create a task that starts and ends during the trace.
    39  	ctx3, t3 := trace.NewTask(baseCtx, "type3")
    40  
    41  	// Generate some events.
    42  	for i := 0; i < 2; i++ {
    43  		do(baseCtx, 4)
    44  		do(ctx0, 2)
    45  		do(ctx1, 3)
    46  		do(ctx2, 6)
    47  		do(ctx3, 5)
    48  	}
    49  
    50  	// Finish up tasks according to their lifetime relative to the trace.
    51  	t3.End()
    52  	trace.Stop()
    53  	t2.End()
    54  	t0.End()
    55  }
    56  
    57  func do(ctx context.Context, k int) {
    58  	trace.Log(ctx, "log", "before do")
    59  
    60  	var t *trace.Task
    61  	ctx, t = trace.NewTask(ctx, "do")
    62  	defer t.End()
    63  
    64  	trace.Log(ctx, "log2", "do")
    65  
    66  	// Create a region and spawn more tasks and more workers.
    67  	trace.WithRegion(ctx, "fanout", func() {
    68  		for i := 0; i < k; i++ {
    69  			go func(i int) {
    70  				trace.WithRegion(ctx, fmt.Sprintf("region%d", i), func() {
    71  					trace.Logf(ctx, "log", "fanout region%d", i)
    72  					if i == 2 {
    73  						do(ctx, 0)
    74  						return
    75  					}
    76  				})
    77  			}(i)
    78  		}
    79  	})
    80  
    81  	// Sleep to let things happen, but also increase the chance that we
    82  	// advance a generation.
    83  	time.Sleep(10 * time.Millisecond)
    84  }
    85
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