Re: about mutex of multithreaded program
On Apr 24, 7:28 am, "lfeiman...@gmail.com" <lfeiman...@gmail.com>
wrote:
i use these code in a network application ,which has lots of users
about 10,000 clients login and logout in the same time,and those users
are doing something to each other ,so if i use mutex ,the speed is a
big problem,what can i do
If you use a critical section (on Windows) as Ken mentioned, that will
allow you to lock the entire array in very efficient manner. The
difference between a critical section and a mutex is that the critical
section will first try to lock the structure in user-mode using a spin
lock (http://en.wikipedia.org/wiki/Spin_lock), and if the locking by
spin-lock is unsucessful, it will fail-over into the kernel with a
full mutex.
But it appears that you do not need to lock th entire structure. It
appears that, for deletion, you would simply like to remove a pointer
from the vector so that it is no longer considered a candidate for
"doing something." In that case, you would use one of the
Interlocked* functions (or its equivalent on non-Windows OS's). This
will allow you to atomically remove a pointer from consideration. For
example, you could use InterlockedExchangePointer (http://
msdn2.microsoft.com/en-us/library/ms683609.aspx) to nullify an entry
atomically. Both the code that does the iteration for "doing
something" and the code that does the removal would use this function
or its equivalent on non-Windows OS's.
This is the fastest, semi-portable way I can think of that you can do
this. Note that, on Windows, the compiler will try to help you by
making it an intrinsic if possible.
-Le Chaud Lapin-
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