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// Copyright 2013 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.
package debug_test
import (
"internal/testenv"
"runtime"
. "runtime/debug"
"testing"
"time"
)
func TestReadGCStats(t *testing.T) {
defer SetGCPercent(SetGCPercent(-1))
var stats GCStats
var mstats runtime.MemStats
var min, max time.Duration
// First ReadGCStats will allocate, second should not,
// especially if we follow up with an explicit garbage collection.
stats.PauseQuantiles = make([]time.Duration, 10)
ReadGCStats(&stats)
runtime.GC()
// Assume these will return same data: no GC during ReadGCStats.
ReadGCStats(&stats)
runtime.ReadMemStats(&mstats)
if stats.NumGC != int64(mstats.NumGC) {
t.Errorf("stats.NumGC = %d, but mstats.NumGC = %d", stats.NumGC, mstats.NumGC)
}
if stats.PauseTotal != time.Duration(mstats.PauseTotalNs) {
t.Errorf("stats.PauseTotal = %d, but mstats.PauseTotalNs = %d", stats.PauseTotal, mstats.PauseTotalNs)
}
if stats.LastGC.UnixNano() != int64(mstats.LastGC) {
t.Errorf("stats.LastGC.UnixNano = %d, but mstats.LastGC = %d", stats.LastGC.UnixNano(), mstats.LastGC)
}
n := int(mstats.NumGC)
if n > len(mstats.PauseNs) {
n = len(mstats.PauseNs)
}
if len(stats.Pause) != n {
t.Errorf("len(stats.Pause) = %d, want %d", len(stats.Pause), n)
} else {
off := (int(mstats.NumGC) + len(mstats.PauseNs) - 1) % len(mstats.PauseNs)
for i := 0; i < n; i++ {
dt := stats.Pause[i]
if dt != time.Duration(mstats.PauseNs[off]) {
t.Errorf("stats.Pause[%d] = %d, want %d", i, dt, mstats.PauseNs[off])
}
if max < dt {
max = dt
}
if min > dt || i == 0 {
min = dt
}
off = (off + len(mstats.PauseNs) - 1) % len(mstats.PauseNs)
}
}
q := stats.PauseQuantiles
nq := len(q)
if q[0] != min || q[nq-1] != max {
t.Errorf("stats.PauseQuantiles = [%d, ..., %d], want [%d, ..., %d]", q[0], q[nq-1], min, max)
}
for i := 0; i < nq-1; i++ {
if q[i] > q[i+1] {
t.Errorf("stats.PauseQuantiles[%d]=%d > stats.PauseQuantiles[%d]=%d", i, q[i], i+1, q[i+1])
}
}
// compare memory stats with gc stats:
if len(stats.PauseEnd) != n {
t.Fatalf("len(stats.PauseEnd) = %d, want %d", len(stats.PauseEnd), n)
}
off := (int(mstats.NumGC) + len(mstats.PauseEnd) - 1) % len(mstats.PauseEnd)
for i := 0; i < n; i++ {
dt := stats.PauseEnd[i]
if dt.UnixNano() != int64(mstats.PauseEnd[off]) {
t.Errorf("stats.PauseEnd[%d] = %d, want %d", i, dt.UnixNano(), mstats.PauseEnd[off])
}
off = (off + len(mstats.PauseEnd) - 1) % len(mstats.PauseEnd)
}
}
var big = make([]byte, 1<<20)
func TestFreeOSMemory(t *testing.T) {
var ms1, ms2 runtime.MemStats
if big == nil {
t.Skip("test is not reliable when run multiple times")
}
big = nil
runtime.GC()
runtime.ReadMemStats(&ms1)
FreeOSMemory()
runtime.ReadMemStats(&ms2)
if ms1.HeapReleased >= ms2.HeapReleased {
t.Errorf("released before=%d; released after=%d; did not go up", ms1.HeapReleased, ms2.HeapReleased)
}
}
var (
setGCPercentBallast interface{}
setGCPercentSink interface{}
)
func TestSetGCPercent(t *testing.T) {
testenv.SkipFlaky(t, 20076)
// Test that the variable is being set and returned correctly.
old := SetGCPercent(123)
new := SetGCPercent(old)
if new != 123 {
t.Errorf("SetGCPercent(123); SetGCPercent(x) = %d, want 123", new)
}
// Test that the percentage is implemented correctly.
defer func() {
SetGCPercent(old)
setGCPercentBallast, setGCPercentSink = nil, nil
}()
SetGCPercent(100)
runtime.GC()
// Create 100 MB of live heap as a baseline.
const baseline = 100 << 20
var ms runtime.MemStats
runtime.ReadMemStats(&ms)
setGCPercentBallast = make([]byte, baseline-ms.Alloc)
runtime.GC()
runtime.ReadMemStats(&ms)
if abs64(baseline-int64(ms.Alloc)) > 10<<20 {
t.Fatalf("failed to set up baseline live heap; got %d MB, want %d MB", ms.Alloc>>20, baseline>>20)
}
// NextGC should be ~200 MB.
const thresh = 20 << 20 // TODO: Figure out why this is so noisy on some builders
if want := int64(2 * baseline); abs64(want-int64(ms.NextGC)) > thresh {
t.Errorf("NextGC = %d MB, want %d±%d MB", ms.NextGC>>20, want>>20, thresh>>20)
}
// Create some garbage, but not enough to trigger another GC.
for i := 0; i < int(1.2*baseline); i += 1 << 10 {
setGCPercentSink = make([]byte, 1<<10)
}
setGCPercentSink = nil
// Adjust GOGC to 50. NextGC should be ~150 MB.
SetGCPercent(50)
runtime.ReadMemStats(&ms)
if want := int64(1.5 * baseline); abs64(want-int64(ms.NextGC)) > thresh {
t.Errorf("NextGC = %d MB, want %d±%d MB", ms.NextGC>>20, want>>20, thresh>>20)
}
// Trigger a GC and get back to 100 MB live with GOGC=100.
SetGCPercent(100)
runtime.GC()
// Raise live to 120 MB.
setGCPercentSink = make([]byte, int(0.2*baseline))
// Lower GOGC to 10. This must force a GC.
runtime.ReadMemStats(&ms)
ngc1 := ms.NumGC
SetGCPercent(10)
// It may require an allocation to actually force the GC.
setGCPercentSink = make([]byte, 1<<20)
runtime.ReadMemStats(&ms)
ngc2 := ms.NumGC
if ngc1 == ngc2 {
t.Errorf("expected GC to run but it did not")
}
}
func abs64(a int64) int64 {
if a < 0 {
return -a
}
return a
}
func TestSetMaxThreadsOvf(t *testing.T) {
// Verify that a big threads count will not overflow the int32
// maxmcount variable, causing a panic (see Issue 16076).
//
// This can only happen when ints are 64 bits, since on platforms
// with 32 bit ints SetMaxThreads (which takes an int parameter)
// cannot be given anything that will overflow an int32.
//
// Call SetMaxThreads with 1<<31, but only on 64 bit systems.
nt := SetMaxThreads(1 << (30 + ^uint(0)>>63))
SetMaxThreads(nt) // restore previous value
}
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