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.

	for i := range big {
		big[i] = pattern
	}

	// Disable GC for the duration of the test.
	// This avoids a potential GC deadlock when spinning in uninterruptible ASM below #49695.
	defer debug.SetGCPercent(debug.SetGCPercent(-1))
	// SetGCPercent waits until the mark phase is over, but the runtime
	// also preempts at the start of the sweep phase, so make sure that's
	// done too. See #49695.
	runtime.GC()

func stackSwitchCallback() {
	// We want to trigger a bounds check on the g0 stack. To do this, we
	// need to call a splittable function through systemstack().
	// SetGCPercent contains such a systemstack call.
	gogc := debug.SetGCPercent(100)
	debug.SetGCPercent(gogc)
}

// Regression test for https://go.dev/issue/62440. It should be possible for C
// threads to call into Go from different stacks without crashing due to g0

#include <CoreFoundation/CoreFoundation.h>
*/
import "C"
import (
	"runtime/debug"
	"testing"
	"unsafe"
)

func test21897(t *testing.T) {
	// Please write barrier, kick in soon.
	defer debug.SetGCPercent(debug.SetGCPercent(1))

	for i := 0; i < 10000; i++ {
		testCFNumberRef()
		testCFDateRef()
		testCFBooleanRef()
		// Allocate some memory, so eventually the write barrier is enabled

	// If runtime triggers a forced GC during this test then it will deadlock,
	// since the goroutines can't be stopped/preempted.
	// Disable GC for this test (see issue #10958).
	defer debug.SetGCPercent(debug.SetGCPercent(-1))
	// SetGCPercent waits until the mark phase is over, but the runtime
	// also preempts at the start of the sweep phase, so make sure that's
	// done too. See #45867.
	runtime.GC()
	for try := 0; try < N; try++ {

	if err != nil {
		t.Fatal(err)
	}

	// Run test with GOGC=10, to make bug more likely.
	// Without the KeepAlives, the loop usually dies after
	// about 30 iterations.
	defer debug.SetGCPercent(debug.SetGCPercent(10))
	for n := 0; n < 200; n++ {
		// Clear the underlying BoringCrypto object cache.
		privCache.Clear()

		// Race to create the underlying BoringCrypto object.

	// If runtime triggers a forced GC during this test then it will deadlock,
	// since the goroutines can't be stopped/preempted.
	// Disable GC for this test (see issue #10958).
	defer debug.SetGCPercent(debug.SetGCPercent(-1))
	// SetGCPercent waits until the mark phase is over, but the runtime
	// also preempts at the start of the sweep phase, so make sure that's
	// done too.
	GC()

	doTestParallelReaders(1)
	doTestParallelReaders(3)

import (
	"runtime"
	"runtime/debug"
	"unsafe"
)

func init() {
	register("BadTraceback", BadTraceback)
}

func BadTraceback() {
	// Disable GC to prevent traceback at unexpected time.
	debug.SetGCPercent(-1)
	// Out of an abundance of caution, also make sure that there are
	// no GCs actively in progress.
	runtime.GC()

	// Run badLR1 on its own stack to minimize the stack size and

	// InjectDebugCall cannot be executed while a GC is actively in
	// progress. Wait until the current GC is done, and turn it off.
	//
	// See #49370.
	runtime.GC()
	defer debug.SetGCPercent(debug.SetGCPercent(-1))

	// Test that the runtime refuses call injection at unsafe points.
	var g *runtime.G
	var ready, stop uint32
	defer atomic.StoreUint32(&stop, 1)
	go debugCallUnsafePointWorker(&g, &ready, &stop)

import (
	"runtime"
	"runtime/debug"
	"slices"
	. "sync"
	"sync/atomic"
	"testing"
	"time"
)

func TestPool(t *testing.T) {
	// disable GC so we can control when it happens.
	defer debug.SetGCPercent(debug.SetGCPercent(-1))
	var p Pool
	if p.Get() != nil {
		t.Fatal("expected empty")
	}

	// Make sure that the goroutine doesn't migrate to another P
	// between Put and Get calls.
	Runtime_procPin()
	p.Put("a")