Name: ccC48265 Date: 11/20/97


There is a general issue in that a high throughput multi-threaded application
which is
run on different platforms behaves in different ways. Are there any threading
guidelines
to help reduce this problem?
(Review ID: 20505)
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###@###.### -- 97-11-24:

Here is some further detail from the original incident submitter that
should help in further clarifying the bug:

On NT, changing a thread's priority does not seem to have any significant
effect until the priority is set to MAX_PRIORITY.

Consider a system with a number of threads, all running at priority 5.
One of these threads is the main thread of execution that requires most
of the processor time.

To achieve this, the priority of the thread is set to 10 (which is the
maximum for the thread group). This has the desired effect in that the
overall system executes much more quickly (approximately twice as fast
as with all threads at priority 5), but has the side-effect that no other
thread is allocated ANY processor time at all.

However, when the priority is reduced to 9, the system operates no
differently than with all priorities set to 5. There does not seem to
be a gradual curve when moving priorities from 6 through to 9 - only
when the priority is set to 10 is there any effect, and then it is a
total switch.

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