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      1 // Copyright 2013 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 package debug
      6 
      7 import (
      8 	"runtime"
      9 	"testing"
     10 	"time"
     11 )
     12 
     13 func TestReadGCStats(t *testing.T) {
     14 	defer SetGCPercent(SetGCPercent(-1))
     15 
     16 	var stats GCStats
     17 	var mstats runtime.MemStats
     18 	var min, max time.Duration
     19 
     20 	// First ReadGCStats will allocate, second should not,
     21 	// especially if we follow up with an explicit garbage collection.
     22 	stats.PauseQuantiles = make([]time.Duration, 10)
     23 	ReadGCStats(&stats)
     24 	runtime.GC()
     25 
     26 	// Assume these will return same data: no GC during ReadGCStats.
     27 	ReadGCStats(&stats)
     28 	runtime.ReadMemStats(&mstats)
     29 
     30 	if stats.NumGC != int64(mstats.NumGC) {
     31 		t.Errorf("stats.NumGC = %d, but mstats.NumGC = %d", stats.NumGC, mstats.NumGC)
     32 	}
     33 	if stats.PauseTotal != time.Duration(mstats.PauseTotalNs) {
     34 		t.Errorf("stats.PauseTotal = %d, but mstats.PauseTotalNs = %d", stats.PauseTotal, mstats.PauseTotalNs)
     35 	}
     36 	if stats.LastGC.UnixNano() != int64(mstats.LastGC) {
     37 		t.Errorf("stats.LastGC.UnixNano = %d, but mstats.LastGC = %d", stats.LastGC.UnixNano(), mstats.LastGC)
     38 	}
     39 	n := int(mstats.NumGC)
     40 	if n > len(mstats.PauseNs) {
     41 		n = len(mstats.PauseNs)
     42 	}
     43 	if len(stats.Pause) != n {
     44 		t.Errorf("len(stats.Pause) = %d, want %d", len(stats.Pause), n)
     45 	} else {
     46 		off := (int(mstats.NumGC) + len(mstats.PauseNs) - 1) % len(mstats.PauseNs)
     47 		for i := 0; i < n; i++ {
     48 			dt := stats.Pause[i]
     49 			if dt != time.Duration(mstats.PauseNs[off]) {
     50 				t.Errorf("stats.Pause[%d] = %d, want %d", i, dt, mstats.PauseNs[off])
     51 			}
     52 			if max < dt {
     53 				max = dt
     54 			}
     55 			if min > dt || i == 0 {
     56 				min = dt
     57 			}
     58 			off = (off + len(mstats.PauseNs) - 1) % len(mstats.PauseNs)
     59 		}
     60 	}
     61 
     62 	q := stats.PauseQuantiles
     63 	nq := len(q)
     64 	if q[0] != min || q[nq-1] != max {
     65 		t.Errorf("stats.PauseQuantiles = [%d, ..., %d], want [%d, ..., %d]", q[0], q[nq-1], min, max)
     66 	}
     67 
     68 	for i := 0; i < nq-1; i++ {
     69 		if q[i] > q[i+1] {
     70 			t.Errorf("stats.PauseQuantiles[%d]=%d > stats.PauseQuantiles[%d]=%d", i, q[i], i+1, q[i+1])
     71 		}
     72 	}
     73 
     74 	// compare memory stats with gc stats:
     75 	if len(stats.PauseEnd) != n {
     76 		t.Fatalf("len(stats.PauseEnd) = %d, want %d", len(stats.PauseEnd), n)
     77 	}
     78 	off := (int(mstats.NumGC) + len(mstats.PauseEnd) - 1) % len(mstats.PauseEnd)
     79 	for i := 0; i < n; i++ {
     80 		dt := stats.PauseEnd[i]
     81 		if dt.UnixNano() != int64(mstats.PauseEnd[off]) {
     82 			t.Errorf("stats.PauseEnd[%d] = %d, want %d", i, dt, mstats.PauseEnd[off])
     83 		}
     84 		off = (off + len(mstats.PauseEnd) - 1) % len(mstats.PauseEnd)
     85 	}
     86 }
     87 
     88 var big = make([]byte, 1<<20)
     89 
     90 func TestFreeOSMemory(t *testing.T) {
     91 	if runtime.GOARCH == "arm64" || runtime.GOARCH == "ppc64" || runtime.GOARCH == "ppc64le" ||
     92 		runtime.GOOS == "nacl" {
     93 		t.Skip("issue 9993; scavenger temporarily disabled on systems with physical pages larger than logical pages")
     94 	}
     95 	var ms1, ms2 runtime.MemStats
     96 
     97 	if big == nil {
     98 		t.Skip("test is not reliable when run multiple times")
     99 	}
    100 	big = nil
    101 	runtime.GC()
    102 	runtime.ReadMemStats(&ms1)
    103 	FreeOSMemory()
    104 	runtime.ReadMemStats(&ms2)
    105 	if ms1.HeapReleased >= ms2.HeapReleased {
    106 		t.Errorf("released before=%d; released after=%d; did not go up", ms1.HeapReleased, ms2.HeapReleased)
    107 	}
    108 }
    109 
    110 func TestSetGCPercent(t *testing.T) {
    111 	// Test that the variable is being set and returned correctly.
    112 	// Assume the percentage itself is implemented fine during GC,
    113 	// which is harder to test.
    114 	old := SetGCPercent(123)
    115 	new := SetGCPercent(old)
    116 	if new != 123 {
    117 		t.Errorf("SetGCPercent(123); SetGCPercent(x) = %d, want 123", new)
    118 	}
    119 }
    120