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Hi, everybody
I found that RedHat 7.3 probably have bugs with Real-time scheduler.
I have run test programs to assess priority inversion of TAO on both Windows
2000 and Redhat Linux. Results from Win2000 are good but the problem
bothering me last two days is that the real-time priority of a thread in
RedHat 7.3 seems not to work and the higher priority task do not have
significant precedence over the lower ones. I could not identify where the
problem was until this evening I use a process monitoring tool called qps
that can change the scheduling policies and priorities at run-time. It is
revealed that changes to the real-time priority have little impact on
behavior of real-time threads. In contrast, changes to dynamic priorities of
threads in time-sharing scheduling class with "nice" have much more
noticeable effect
on the CPU time allocation among threads. I suspect that something is wrong
with the scheduler. So I run the exactly the same test programs on another
RedHat 7.0 machine in SEDAL lab. The results are perfect
and consist with other researchers' results regarding real-time support of
COTS operating systems.
My RedHat 7.3 is 6 CD with the red cover installation manual, which is
distributed by RedHat directly rather that intermediate re-copiers
Jeff Z
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