Hi Fu (without n)
Luotao Fu wrote:
Hi Wolfgang,
Wolfgang Grandegger wrote:
Hi Fun,
What's so funny? ;-)
Ah, oh, just a funny typo ;-).
[...]
But as Steven pointed out, the preempt_enable_noresched at that place
might be illegal, anyway. In 2.6.25-rt, trace_mark() is no longer
used and I do not see an improvement with CONFIG_RCU_TRAC any more.
Latencies go up to 600us. I also tried with CONFIG_RCU_BOOST
disabled, but it did not improve the latencies. Actually, I still
measure significantly different latencies with 2.6.24.4-rt4,
2.6.24.7-rt14 and 2.6.25.8-rt7, which is quite frustrating. As you
seem not be able to reproduce my high latencies, I wonder if there
are some toolchain or glibc related issues.
I took a quick look into the rcppreempt boost stuff in 2.6.24-rt and
2.6.25-rt. As you have mentioned, trace_mark is no more used in
2.6.24-rt. Instead of that flags are used to detect if the task is
preempted. It might indeed probably be some toolchain issue.
My powerpc toolchain I'm using here contains gcc 4.1.2 and glibc 2.5
OK, in the past you have been able to reproduce the high latencies with
2.6.24-rt1 and CONFIG_RCU_TRACE disabled, IIRC. Did you use a different
toolchain at that time?
Wolfgang.
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