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Fix bug: bad critical section for multiple values #237

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Merged
merged 1 commit into from
Jan 29, 2019
Merged

Fix bug: bad critical section for multiple values #237

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6 changes: 4 additions & 2 deletions rpc/rpcutil.go
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Original file line number Diff line number Diff line change
Expand Up @@ -182,7 +182,9 @@ func recordRPCCost(startTime time.Time, method string, err error) {
// Optimistically, val will not be nil except the first Call of method
// expvar uses sync.Map
// So, we try it first without lock
if val = expvar.Get(name); val == nil {
val = expvar.Get(name)
valC = expvar.Get(nameC)
if val == nil || valC == nil {
callRPCExpvarLock.Lock()
val = expvar.Get(name)
if val == nil {
Expand All @@ -191,9 +193,9 @@ func recordRPCCost(startTime time.Time, method string, err error) {
}
callRPCExpvarLock.Unlock()
val = expvar.Get(name)
valC = expvar.Get(nameC)
}
val.(mw.Metric).Add(costTime.Seconds())
valC = expvar.Get(nameC)
valC.(mw.Metric).Add(1)
return
}
Expand Down
26 changes: 26 additions & 0 deletions rpc/rpcutil_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@ package rpc

import (
"context"
"fmt"
"os"
"path/filepath"
"runtime"
Expand Down Expand Up @@ -443,3 +444,28 @@ func BenchmarkPersistentCaller_Call(b *testing.B) {

server.Stop()
}

func TestRecordRPCCost(t *testing.T) {
Convey("Bug: bad critical section for multiple values", t, func(c C) {
var (
start = time.Now()
rounds = 1000
concurrent = 10
wg = &sync.WaitGroup{}
body = func(i int) {
defer func() {
c.So(recover(), ShouldBeNil)
wg.Done()
}()
recordRPCCost(start, fmt.Sprintf("M%d", i), nil)
}
)
defer wg.Wait()
for i := 0; i < rounds; i++ {
for j := 0; j < concurrent; j++ {
wg.Add(1)
go body(i)
}
}
})
}