for pb.Next() {
			Runtime_Semrelease(&sem.sem, false, 0)
			Runtime_Semacquire(&sem.sem)
		}
	})
}

func benchmarkSema(b *testing.B, block, work bool) {
	if b.N == 0 {
		return
	}
	sem := uint32(0)
	if block {
		done := make(chan bool)
		go func() {
			for p := 0; p < runtime.GOMAXPROCS(0)/2; p++ {
				Runtime_Semacquire(&sem)
			}
			done <- true
		}()
		defer func() {
			<-done
		}()

// 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 sync

// Export for testing.
var Runtime_Semacquire = runtime_Semacquire
var Runtime_Semrelease = runtime_Semrelease
var Runtime_procPin = runtime_procPin
var Runtime_procUnpin = runtime_procUnpin

// poolDequeue testing.
type PoolDequeue interface {
	PushHead(val any) bool

// Semacquire waits until *s > 0 and then atomically decrements it.
// It is intended as a simple sleep primitive for use by the synchronization
// library and should not be used directly.
func runtime_Semacquire(s *uint32)

// Semacquire(RW)Mutex(R) is like Semacquire, but for profiling contended
// Mutexes and RWMutexes.
// If lifo is true, queue waiter at the head of wait queue.

			new = old + mutexWait
			if new&mutexMask == 0 {
				panic(overflowMsg)
			}
		}
		if atomic.CompareAndSwapUint64(&mu.state, old, new) {
			if old&mutexBit == 0 {
				return true
			}
			runtime_Semacquire(mutexSema)
			// The signaller has subtracted mutexWait.
		}
	}
}

// unlock removes a reference from mu and unlocks mu.
// It reports whether there is no remaining reference.

				// As a consequence, can do the write only for the first waiter,
				// otherwise concurrent Waits will race with each other.
				race.Write(unsafe.Pointer(&wg.sema))
			}
			runtime_Semacquire(&wg.sema)
			if wg.state.Load() != 0 {
				panic("sync: WaitGroup is reused before previous Wait has returned")
			}
			if race.Enabled {
				race.Enable()
				race.Acquire(unsafe.Pointer(wg))
			}

	"internal/testenv"
	"os"
	"os/exec"
	"runtime"
	"strings"
	. "sync"
	"testing"
	"time"
)

func HammerSemaphore(s *uint32, loops int, cdone chan bool) {
	for i := 0; i < loops; i++ {
		Runtime_Semacquire(s)
		Runtime_Semrelease(s, false, 0)
	}
	cdone <- true
}

func TestSemaphore(t *testing.T) {
	s := new(uint32)
	*s = 1
	c := make(chan bool)
	for i := 0; i < 10; i++ {

//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname sync_runtime_Semacquire sync.runtime_Semacquire
func sync_runtime_Semacquire(addr *uint32) {
	semacquire1(addr, false, semaBlockProfile, 0, waitReasonSemacquire)
}

//go:linkname poll_runtime_Semacquire internal/poll.runtime_Semacquire
func poll_runtime_Semacquire(addr *uint32) {
	semacquire1(addr, false, semaBlockProfile, 0, waitReasonSemacquire)
}

	// may be blocking, and that would block the Close.
	// No need for an atomic read of isBlocking, increfAndClose means
	// we have exclusive access to fd.
	if fd.isBlocking == 0 {
		runtime_Semacquire(&fd.csema)
	}

	return err
}

// SetBlocking puts the file into blocking mode.
func (fd *FD) SetBlocking() error {
	if err := fd.incref(); err != nil {
		return err
	}

	}
	// unblock pending reader and writer
	fd.pd.evict()
	err := fd.decref()
	// Wait until the descriptor is closed. If this was the only
	// reference, it is already closed.
	runtime_Semacquire(&fd.csema)
	return err
}

// Windows ReadFile and WSARecv use DWORD (uint32) parameter to pass buffer length.
// This prevents us reading blocks larger than 4GB.
// See golang.org/issue/26923.