Le 25/02/2015 15:41, Xiangrong Fang a écrit :
Hi All,
Can I use Sleep() in a thread to give up cpu time to other threads
running at the same time, so as to adjust the relative "niceness" of a
group of workers working on the same subject (in which each thread
take part of the whole task).
Thanks!
Xiangrong
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Coming back to the initial message, I've had to solve a similar problem
a year ago. A bunch of threads had to do do some job each one related to
a database. Jobs to do were coming from the main thread (a service) and
some results and messages where held and processed by the same main
thread. The main problem was that all threads had to take care from
incoming messages.
For tthese reasons I implemented the threads with a loop where the last
instruction was a WaitForMultipleObjects. The events where hosted and
set in the main thread which fired the events when something was to be
done by the relevant thread. This way, when the thread had nothning to
do, the WaitFor... passed the control to the kernel and entered a sleep
state. But if an incoming job was posted, the event fired did awake the
corresponding thread. Some other threads did not wait for any external
job, so the WaitFor... was replaced by a simple Sleep. This helped me to
implement an internal thread safe message queue. Another problem solved
was a front end program using Indy and TCP/IP listener using non
blocking sockets, to be reactive to more than 20 active TCP/IP clients
sending messages for about 10 in a second for each client. The front end
program managed all this incoming traffic showing that all client
threads were working almost "at the same time". Using events the main
program was able to send user commands to the "sleepeng" threads and
seeing them be executed at once.
So using either Sleep or events depends on what the thread is supposed
to do and what are the incoming signals if any. Using Sleep nothing can
reach the sleeping thread whilst waiting for events stops the thread
until something has to be done. On the other hand a periodical awake
period using the WaitFor... timeout.
Antonio.
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