sometimes ReleaseSemaphore takes long time, why?

[kalven]

Hi, everyone

I has one thread A (producer), and thread B(consumer).
A get the data from a buffer in DSP hardware , and then ReleaseSemaphore.
B wait the semaphore and process the data.

With some complex UI operations, ReleaseSemaphore takes long time occassionaly. why?

[MrViggy]

What OS? What hardware?

Viggy

[kalven]

i am sorry, i am not take it clearly.
i am doing with a little complex system.
Take it simply:
1, PCI driver get the data from the buffer in DSP hardware, and them buffer the data.
2, Thread A in PC(windows XP SP2 OS) read the data from PCI buffer, and then Release the Semaphore, which is Waited by Thread B
3, Thread B return from WaitForMultiObjects, and process the data.

the problem is sometimes function ReleaseSemaphore takes time longer than it should.

[MikeAThon]

Define "long time". Remember that Windows is not a real-time OS, and anything less than a few thread time-slices and context-switches is expected. So, assuming a thread time-slice of around 60 milliseconds, anything less than around 200 milliseconds should be expected.

Mike