Hello... > both have advantages/disadvantages and restrictions, therefore they > are used under (very) different circumstances. refer to a good kernel > book for details (LDD3 has already been recommended to you - > http://lwn.net/Kernel/LDD3/). Just to add what Florin said. Busy wait is preferred if you are planning to wait for such a short time ("short" here are relative to your CPU clock, perhaps under 1-2 ms), because the process is still running and able to quickly grab the lock ASAP. In the other hand, sleeping lock (e.g semaphore) is preferred if you want to sleep for long time (again "long" is relative), for example 10 seconds. Since the process is put on TASK_(UN)INTERRUPTIBLE and moved out from run queue, the CPU is free to do something else or simply go to idle state. regards Mulyadi. -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
