Files
zrepl/util/semaphore/semaphore_test.go
Christian Schwarz 1ae087bfcf [WIP] add and use tracing API as part of package logging
- make `logging.GetLogger(ctx, Subsys)` the authoritative `logger.Logger` factory function
    - the context carries a linked list of injected fields which
      `logging.GetLogger` adds to the logger it returns
- introduce the concept of tasks and spans, also tracked as linked list within ctx
    - [ ] TODO automatic logging of span begins and ends, with a unique
      ID stack that makes it easy to follow a series of log entries in
      concurrent code
    - ability to produce a chrome://tracing-compatible trace file,
      either via an env variable or a `zrepl pprof` subcommand
        - this is not a CPU profile, we already have go pprof for that
        - but it is very useful to visually inspect where the
          replication / snapshotter / pruner spends its time
          ( fixes #307 )
2020-04-25 11:16:59 +02:00

57 lines
1.1 KiB
Go

package semaphore
import (
"context"
"sync"
"sync/atomic"
"testing"
"time"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"github.com/zrepl/zrepl/daemon/logging"
)
func TestSemaphore(t *testing.T) {
const numGoroutines = 10
const concurrentSemaphore = 5
const sleepTime = 1 * time.Second
begin := time.Now()
sem := New(concurrentSemaphore)
var acquisitions struct {
beforeT, afterT uint32
}
ctx := context.Background()
defer logging.WithTaskFromStackUpdateCtx(&ctx)()
var wg sync.WaitGroup
wg.Add(numGoroutines)
for i := 0; i < numGoroutines; i++ {
go func() {
ctx, end := logging.WithTaskFromStack(ctx)
defer end()
defer wg.Done()
res, err := sem.Acquire(ctx)
require.NoError(t, err)
defer res.Release()
if time.Since(begin) > sleepTime {
atomic.AddUint32(&acquisitions.beforeT, 1)
} else {
atomic.AddUint32(&acquisitions.afterT, 1)
}
time.Sleep(sleepTime)
}()
}
wg.Wait()
assert.True(t, acquisitions.beforeT == concurrentSemaphore)
assert.True(t, acquisitions.afterT == numGoroutines-concurrentSemaphore)
}