BIG PIPE TIMESLICE MANUAL
BIG PIPE TIMESLICE WINDOWS

Instead, the calling thread can acquire ownership of the critical section if it is released during the spin operation. Immediately call WaitForSingleObject when contention occurs. However, if the spin count is set properly, the calling thread does not In the worst-case scenario, contention for the critical section is constant, and each thread makes anĮxpensive call to the WaitForSingleObject function. It is because if the object is not immediately available, the thread relinquishes its processor time slice.

The part we disagree is because I say waiting on an object is expensive. Move to WaitForSingleObject() with a timeout of INFINITE.

BIG PIPE TIMESLICE MANUAL

In my previous post I suggested a manual spinlock on a mutex that tries to acquire the lock with WaitForSingleObject() and a timeout of zero, and if after several thousand attempts the lock is still unavailable, But when the spinlock reaches max-attempts, it's should fall back to a synchronization object, not a timer.Ĭorrect. A spinlock should minimize this impact by retrying the lock a couple thousand times before actually giving up. If you need cancellation, then you can wait for multiple objects: one, your original signal, and the other, a cancellation signal. Your execution is suspended and this puts you on a list of who to be woken up when the object becomes signalled and the context switch will go directly

It's always better to relinquish control by waiting for a synchronization object with infinite timeout. Causing the preemptive context switches at a rate of 1ms is not a good thing either. It's a cop-out often used when there is no other indicator that an event has occurred and state The passage of time doesn't trigger the change of state that one is looking for. Well, it's just not a good idea to use Sleep to relinquish control. , as the OP seem to have experienced by using Sleep(1). Yes, it's always a good idea to minimize context switches. Relinquishing the processor for every loop (potentially) can have a big performance hit Very efficient number of tries without making use of timers before bothering the kernel with context switches and wait-lists. In multi-processor systems, they spin for a They don't sleep when the lock is available, and they relinquish control to the thread that needs to be woken up when releasing a lock. The synchronization objects are very efficient. Waiting on a synchronization object is expensive in this regard for busy processes. If the spinlock fails to acquire a lock, then use WaitForSingleObject() with a timeout of INFINITE to avoid the CPU usage toĪs I understand this, Wyck, the spin is necessary for the exact same reason a critical section has one: To avoid yeilding the processor to another thread if at all possible. To try to acquire the lock use WaitForSingleObject() with a timeout of zero. Unfortunately cannot be used inter-process. See (VS.85).aspx forįinally, my advice: Use a mutex for synchronization (or event or semaphore whichever is best for you) for inter-process synchronization, but make a spinlock loop yourself to mimic the behavior of critical sections, which are probably the fastest but For your particular case, a CRITICAL_SECTION object would have been perferct because it has a configurable spinlock loop. If I were you, I'd try SwitchToThread() to just relinquish processor time slice and return as soon as possible.Īs for your particular problem, it is too bad the synchronization has to be inter-process. I am actually surprised to hear there's a difference between Sleep(0) and Sleep(1)īecause as a minimum, the thread will have to wait for at least 1 processor time slice (not 100% guaranteed, but quite probable).

BIG PIPE TIMESLICE WINDOWS

A call to Sleep() makes the OS suspend the calling thread and any processor time remaining from its slice is lost and Windows will immediately schedule another thread.

Big pipe timeslice