path: root/metrics/runtime_test.go

package metrics

import (
    "runtime"
    "testing"
    "time"
)

func BenchmarkRuntimeMemStats(b *testing.B) {
    r := NewRegistry()
    RegisterRuntimeMemStats(r)
    b.ResetTimer()
    for i := 0; i < b.N; i++ {
        CaptureRuntimeMemStatsOnce(r)
    }
}

func TestRuntimeMemStats(t *testing.T) {
    r := NewRegistry()
    RegisterRuntimeMemStats(r)
    CaptureRuntimeMemStatsOnce(r)
    zero := runtimeMetrics.MemStats.PauseNs.Count() // Get a "zero" since GC may have run before these tests.
    runtime.GC()
    CaptureRuntimeMemStatsOnce(r)
    if count := runtimeMetrics.MemStats.PauseNs.Count(); 1 != count-zero {
        t.Fatal(count - zero)
    }
    runtime.GC()
    runtime.GC()
    CaptureRuntimeMemStatsOnce(r)
    if count := runtimeMetrics.MemStats.PauseNs.Count(); 3 != count-zero {
        t.Fatal(count - zero)
    }
    for i := 0; i < 256; i++ {
        runtime.GC()
    }
    CaptureRuntimeMemStatsOnce(r)
    if count := runtimeMetrics.MemStats.PauseNs.Count(); 259 != count-zero {
        t.Fatal(count - zero)
    }
    for i := 0; i < 257; i++ {
        runtime.GC()
    }
    CaptureRuntimeMemStatsOnce(r)
    if count := runtimeMetrics.MemStats.PauseNs.Count(); 515 != count-zero { // We lost one because there were too many GCs between captures.
        t.Fatal(count - zero)
    }
}

func TestRuntimeMemStatsNumThread(t *testing.T) {
    r := NewRegistry()
    RegisterRuntimeMemStats(r)
    CaptureRuntimeMemStatsOnce(r)

    if value := runtimeMetrics.NumThread.Value(); value < 1 {
        t.Fatalf("got NumThread: %d, wanted at least 1", value)
    }
}

func TestRuntimeMemStatsBlocking(t *testing.T) {
    if g := runtime.GOMAXPROCS(0); g < 2 {
        t.Skipf("skipping TestRuntimeMemStatsBlocking with GOMAXPROCS=%d\n", g)
    }
    ch := make(chan int)
    go testRuntimeMemStatsBlocking(ch)
    var memStats runtime.MemStats
    t0 := time.Now()
    runtime.ReadMemStats(&memStats)
    t1 := time.Now()
    t.Log("i++ during runtime.ReadMemStats:", <-ch)
    go testRuntimeMemStatsBlocking(ch)
    d := t1.Sub(t0)
    t.Log(d)
    time.Sleep(d)
    t.Log("i++ during time.Sleep:", <-ch)
}

func testRuntimeMemStatsBlocking(ch chan int) {
    i := 0
    for {
        select {
        case ch <- i:
            return
        default:
            i++
        }
    }
}