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000d8bba66
ATM, the replication logic sends all dry-run requests in parallel, which might overwhelm the ZFS pool on the sending side. Since we use rpc/dataconn for dry sends, this also opens one TCP connection per dry-run request. Use a sempahore to limit the degree of concurrency where we know it is a problem ATM. As indicated by the comments, the cleaner solution would involve some kind of 'resource exhaustion' error code. refs #161 refs #164
50 lines
946 B
Go
50 lines
946 B
Go
package semaphore
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import (
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"context"
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"sync"
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"sync/atomic"
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"testing"
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"time"
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"github.com/stretchr/testify/assert"
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"github.com/stretchr/testify/require"
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)
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func TestSemaphore(t *testing.T) {
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const numGoroutines = 10
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const concurrentSemaphore = 5
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const sleepTime = 1 * time.Second
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begin := time.Now()
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sem := New(concurrentSemaphore)
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var aquisitions struct {
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beforeT, afterT uint32
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}
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var wg sync.WaitGroup
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wg.Add(numGoroutines)
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for i := 0; i < numGoroutines; i++ {
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go func() {
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defer wg.Done()
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res, err := sem.Acquire(context.Background())
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require.NoError(t, err)
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defer res.Release()
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if time.Since(begin) > sleepTime {
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atomic.AddUint32(&aquisitions.beforeT, 1)
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} else {
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atomic.AddUint32(&aquisitions.afterT, 1)
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}
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time.Sleep(sleepTime)
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}()
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}
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wg.Wait()
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assert.True(t, aquisitions.beforeT == concurrentSemaphore)
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assert.True(t, aquisitions.afterT == numGoroutines-concurrentSemaphore)
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}
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