func (m *Mutex) unlock() {
unlocked := m.state &^ 1
barrier.Memory()
if atomic.AddUintptr(&m.state, ^uintptr(0)) != unlocked {
panic("sync: unlock of unlocked mutex")
}
noos.Event(unlocked).Send()
}
func BenchmarkPool(b *testing.B) {
var p Pool
var wg WaitGroup
n0 := uintptr(b.N)
n := n0
for i := 0; i < runtime.GOMAXPROCS(0); i++ {
wg.Add(1)
go func() {
defer wg.Done()
for atomic.AddUintptr(&n, ^uintptr(0)) < n0 {
for b := 0; b < 100; b++ {
p.Put(1)
p.Get()
}
}
}()
}
wg.Wait()
}
// Signal, to be called after every operation that can un-wait a block, awakens
// all block waiters.
func (b *Block) Signal() {
if atomic.LoadInt32(&b.waiters) == 0 {
return
}
// We either get the lock, wait in pending state until we get the lock,
// or return because somebody else is in a pending state.
//
// The logic for having only _one_ pending wait is as follows:
//
// - Prime calls can observe the counter either before an increment or
// directly after an increment. We must keep a pending signal because
// a prime call observed after an active increment will return on
// Wait from the pending signal.
//
// - We need only need one pending signal because all active prime
// calls will, at worst, observe the actively signaling counter. That
// counter will be incremented by the pending singal.
//
// - All future signals can be collapsed into one pending signal which
// will wake everything that race read the actively signaling counter.
//
// - One pending signal is the same as pathologically racing all
// signals in front of any active Prime calls continuing to their
// Wait. That is, having one pending singal is the _worst case_ of
// processing all signals consecutively.
//
// In summary, anything that called Prime by _now_ cares about either
// this signal or one pending signal. Eliding _all_ signals into one
// pending signal is the _same_ as having all signals race finishing
// immediately before any future Prime call, which would be the worst
// case scenario from a signaling perspective.
if !b.lock.TryLock() {
return
}
atomic.AddUintptr(&b.counter, 1)
b.lock.WUnlock()
b.cond.Broadcast()
}
func AddUintptr(addr *uintptr, delta uintptr) uintptr {
return orig.AddUintptr(addr, delta)
}
func nextID() uintptr {
return atomic.AddUintptr(&nextIteratorID, 1) - 1
}