Hi Jan,
> As an experiment, you could try implementing the cpuid lookup via
> raw_smp_processor_id(), given you use 2.6.20. Hmm, maybe/likely some
> Xenomai tuning is required as well to make sure that the PDA is set
> correctly when a Xenomai task is created/migrated. Results welcome!
I have applied a patch (below) to my SMP kernel 2.6.20.4.
And actually the results are now much better.
I have been back on my "original" kernel version without the oprofile support.
The "original" ipipe.c delivered times of 4.5 us per step with my test project.
The patched ipipe.c (using raw_smp_processor_id()) delivers 1.25 us per step!
This is really an excellent improvement!
I do not know if there are any side effects - if not: why not using this method
instead
of the previous one...
Regards
Mathias
------------------------- patch start ------------------
--- ipipe.c.orig 2007-05-09 16:16:32.000000000 +0200
+++ ipipe.c 2007-05-11 10:00:44.000000000 +0200
@@ -74,6 +74,7 @@
static notrace int __ipipe_hard_cpuid(void)
{
+#if 0
unsigned long flags;
int cpu;
@@ -81,6 +82,9 @@
cpu = __ipipe_apicid_2_cpu[GET_APIC_ID(apic_read(APIC_ID))];
local_irq_restore_hw_notrace(flags);
return cpu;
+#endif
+ return raw_smp_processor_id();
+
}
#endif /* CONFIG_SMP */
------------------------- patch end ------------------
--
Mathias Koehrer
[EMAIL PROTECTED]
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