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-rw-r--r--src/runtime/stack_test.go397
1 files changed, 397 insertions, 0 deletions
diff --git a/src/runtime/stack_test.go b/src/runtime/stack_test.go
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+++ b/src/runtime/stack_test.go
@@ -0,0 +1,397 @@
+// Copyright 2012 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 runtime_test
+
+import (
+ . "runtime"
+ "strings"
+ "sync"
+ "testing"
+ "time"
+)
+
+// TestStackMem measures per-thread stack segment cache behavior.
+// The test consumed up to 500MB in the past.
+func TestStackMem(t *testing.T) {
+ const (
+ BatchSize = 32
+ BatchCount = 256
+ ArraySize = 1024
+ RecursionDepth = 128
+ )
+ if testing.Short() {
+ return
+ }
+ defer GOMAXPROCS(GOMAXPROCS(BatchSize))
+ s0 := new(MemStats)
+ ReadMemStats(s0)
+ for b := 0; b < BatchCount; b++ {
+ c := make(chan bool, BatchSize)
+ for i := 0; i < BatchSize; i++ {
+ go func() {
+ var f func(k int, a [ArraySize]byte)
+ f = func(k int, a [ArraySize]byte) {
+ if k == 0 {
+ time.Sleep(time.Millisecond)
+ return
+ }
+ f(k-1, a)
+ }
+ f(RecursionDepth, [ArraySize]byte{})
+ c <- true
+ }()
+ }
+ for i := 0; i < BatchSize; i++ {
+ <-c
+ }
+
+ // The goroutines have signaled via c that they are ready to exit.
+ // Give them a chance to exit by sleeping. If we don't wait, we
+ // might not reuse them on the next batch.
+ time.Sleep(10 * time.Millisecond)
+ }
+ s1 := new(MemStats)
+ ReadMemStats(s1)
+ consumed := int64(s1.StackSys - s0.StackSys)
+ t.Logf("Consumed %vMB for stack mem", consumed>>20)
+ estimate := int64(8 * BatchSize * ArraySize * RecursionDepth) // 8 is to reduce flakiness.
+ if consumed > estimate {
+ t.Fatalf("Stack mem: want %v, got %v", estimate, consumed)
+ }
+ // Due to broken stack memory accounting (http://golang.org/issue/7468),
+ // StackInuse can decrease during function execution, so we cast the values to int64.
+ inuse := int64(s1.StackInuse) - int64(s0.StackInuse)
+ t.Logf("Inuse %vMB for stack mem", inuse>>20)
+ if inuse > 4<<20 {
+ t.Fatalf("Stack inuse: want %v, got %v", 4<<20, inuse)
+ }
+}
+
+// Test stack growing in different contexts.
+func TestStackGrowth(t *testing.T) {
+ t.Parallel()
+ var wg sync.WaitGroup
+
+ // in a normal goroutine
+ wg.Add(1)
+ go func() {
+ defer wg.Done()
+ growStack()
+ }()
+ wg.Wait()
+
+ // in locked goroutine
+ wg.Add(1)
+ go func() {
+ defer wg.Done()
+ LockOSThread()
+ growStack()
+ UnlockOSThread()
+ }()
+ wg.Wait()
+
+ // in finalizer
+ wg.Add(1)
+ go func() {
+ defer wg.Done()
+ done := make(chan bool)
+ go func() {
+ s := new(string)
+ SetFinalizer(s, func(ss *string) {
+ growStack()
+ done <- true
+ })
+ s = nil
+ done <- true
+ }()
+ <-done
+ GC()
+ select {
+ case <-done:
+ case <-time.After(20 * time.Second):
+ t.Fatal("finalizer did not run")
+ }
+ }()
+ wg.Wait()
+}
+
+// ... and in init
+//func init() {
+// growStack()
+//}
+
+func growStack() {
+ n := 1 << 10
+ if testing.Short() {
+ n = 1 << 8
+ }
+ for i := 0; i < n; i++ {
+ x := 0
+ growStackIter(&x, i)
+ if x != i+1 {
+ panic("stack is corrupted")
+ }
+ }
+ GC()
+}
+
+// This function is not an anonymous func, so that the compiler can do escape
+// analysis and place x on stack (and subsequently stack growth update the pointer).
+func growStackIter(p *int, n int) {
+ if n == 0 {
+ *p = n + 1
+ GC()
+ return
+ }
+ *p = n + 1
+ x := 0
+ growStackIter(&x, n-1)
+ if x != n {
+ panic("stack is corrupted")
+ }
+}
+
+func TestStackGrowthCallback(t *testing.T) {
+ t.Parallel()
+ var wg sync.WaitGroup
+
+ // test stack growth at chan op
+ wg.Add(1)
+ go func() {
+ defer wg.Done()
+ c := make(chan int, 1)
+ growStackWithCallback(func() {
+ c <- 1
+ <-c
+ })
+ }()
+
+ // test stack growth at map op
+ wg.Add(1)
+ go func() {
+ defer wg.Done()
+ m := make(map[int]int)
+ growStackWithCallback(func() {
+ _, _ = m[1]
+ m[1] = 1
+ })
+ }()
+
+ // test stack growth at goroutine creation
+ wg.Add(1)
+ go func() {
+ defer wg.Done()
+ growStackWithCallback(func() {
+ done := make(chan bool)
+ go func() {
+ done <- true
+ }()
+ <-done
+ })
+ }()
+
+ wg.Wait()
+}
+
+func growStackWithCallback(cb func()) {
+ var f func(n int)
+ f = func(n int) {
+ if n == 0 {
+ cb()
+ return
+ }
+ f(n - 1)
+ }
+ for i := 0; i < 1<<10; i++ {
+ f(i)
+ }
+}
+
+// TestDeferPtrs tests the adjustment of Defer's argument pointers (p aka &y)
+// during a stack copy.
+func set(p *int, x int) {
+ *p = x
+}
+func TestDeferPtrs(t *testing.T) {
+ var y int
+
+ defer func() {
+ if y != 42 {
+ t.Errorf("defer's stack references were not adjusted appropriately")
+ }
+ }()
+ defer set(&y, 42)
+ growStack()
+}
+
+type bigBuf [4 * 1024]byte
+
+// TestDeferPtrsGoexit is like TestDeferPtrs but exercises the possibility that the
+// stack grows as part of starting the deferred function. It calls Goexit at various
+// stack depths, forcing the deferred function (with >4kB of args) to be run at
+// the bottom of the stack. The goal is to find a stack depth less than 4kB from
+// the end of the stack. Each trial runs in a different goroutine so that an earlier
+// stack growth does not invalidate a later attempt.
+func TestDeferPtrsGoexit(t *testing.T) {
+ for i := 0; i < 100; i++ {
+ c := make(chan int, 1)
+ go testDeferPtrsGoexit(c, i)
+ if n := <-c; n != 42 {
+ t.Fatalf("defer's stack references were not adjusted appropriately (i=%d n=%d)", i, n)
+ }
+ }
+}
+
+func testDeferPtrsGoexit(c chan int, i int) {
+ var y int
+ defer func() {
+ c <- y
+ }()
+ defer setBig(&y, 42, bigBuf{})
+ useStackAndCall(i, Goexit)
+}
+
+func setBig(p *int, x int, b bigBuf) {
+ *p = x
+}
+
+// TestDeferPtrsPanic is like TestDeferPtrsGoexit, but it's using panic instead
+// of Goexit to run the Defers. Those two are different execution paths
+// in the runtime.
+func TestDeferPtrsPanic(t *testing.T) {
+ for i := 0; i < 100; i++ {
+ c := make(chan int, 1)
+ go testDeferPtrsGoexit(c, i)
+ if n := <-c; n != 42 {
+ t.Fatalf("defer's stack references were not adjusted appropriately (i=%d n=%d)", i, n)
+ }
+ }
+}
+
+func testDeferPtrsPanic(c chan int, i int) {
+ var y int
+ defer func() {
+ if recover() == nil {
+ c <- -1
+ return
+ }
+ c <- y
+ }()
+ defer setBig(&y, 42, bigBuf{})
+ useStackAndCall(i, func() { panic(1) })
+}
+
+// TestPanicUseStack checks that a chain of Panic structs on the stack are
+// updated correctly if the stack grows during the deferred execution that
+// happens as a result of the panic.
+func TestPanicUseStack(t *testing.T) {
+ pc := make([]uintptr, 10000)
+ defer func() {
+ recover()
+ Callers(0, pc) // force stack walk
+ useStackAndCall(100, func() {
+ defer func() {
+ recover()
+ Callers(0, pc) // force stack walk
+ useStackAndCall(200, func() {
+ defer func() {
+ recover()
+ Callers(0, pc) // force stack walk
+ }()
+ panic(3)
+ })
+ }()
+ panic(2)
+ })
+ }()
+ panic(1)
+}
+
+// use about n KB of stack and call f
+func useStackAndCall(n int, f func()) {
+ if n == 0 {
+ f()
+ return
+ }
+ var b [1024]byte // makes frame about 1KB
+ useStackAndCall(n-1+int(b[99]), f)
+}
+
+func useStack(n int) {
+ useStackAndCall(n, func() {})
+}
+
+func growing(c chan int, done chan struct{}) {
+ for n := range c {
+ useStack(n)
+ done <- struct{}{}
+ }
+ done <- struct{}{}
+}
+
+func TestStackCache(t *testing.T) {
+ // Allocate a bunch of goroutines and grow their stacks.
+ // Repeat a few times to test the stack cache.
+ const (
+ R = 4
+ G = 200
+ S = 5
+ )
+ for i := 0; i < R; i++ {
+ var reqchans [G]chan int
+ done := make(chan struct{})
+ for j := 0; j < G; j++ {
+ reqchans[j] = make(chan int)
+ go growing(reqchans[j], done)
+ }
+ for s := 0; s < S; s++ {
+ for j := 0; j < G; j++ {
+ reqchans[j] <- 1 << uint(s)
+ }
+ for j := 0; j < G; j++ {
+ <-done
+ }
+ }
+ for j := 0; j < G; j++ {
+ close(reqchans[j])
+ }
+ for j := 0; j < G; j++ {
+ <-done
+ }
+ }
+}
+
+func TestStackOutput(t *testing.T) {
+ b := make([]byte, 1024)
+ stk := string(b[:Stack(b, false)])
+ if !strings.HasPrefix(stk, "goroutine ") {
+ t.Errorf("Stack (len %d):\n%s", len(stk), stk)
+ t.Errorf("Stack output should begin with \"goroutine \"")
+ }
+}
+
+func TestStackAllOutput(t *testing.T) {
+ b := make([]byte, 1024)
+ stk := string(b[:Stack(b, true)])
+ if !strings.HasPrefix(stk, "goroutine ") {
+ t.Errorf("Stack (len %d):\n%s", len(stk), stk)
+ t.Errorf("Stack output should begin with \"goroutine \"")
+ }
+}
+
+func TestStackPanic(t *testing.T) {
+ // Test that stack copying copies panics correctly. This is difficult
+ // to test because it is very unlikely that the stack will be copied
+ // in the middle of gopanic. But it can happen.
+ // To make this test effective, edit panic.go:gopanic and uncomment
+ // the GC() call just before freedefer(d).
+ defer func() {
+ if x := recover(); x == nil {
+ t.Errorf("recover failed")
+ }
+ }()
+ useStack(32)
+ panic("test panic")
+}
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