On 01/04/2013 11:16 AM, Jan Kiszka wrote:
On 2013-01-04 11:01, Philippe Gerum wrote:
On 01/03/2013 06:57 PM, Jan Kiszka wrote:
On 2013-01-03 18:34, Philippe Gerum wrote:
On 01/03/2013 06:25 PM, Jan Kiszka wrote:
On 2013-01-03 17:27, Philippe Gerum wrote:
On 01/03/2013 04:44 PM, Jan Kiszka wrote:
On 2013-01-03 16:16, Gilles Chanteperdrix wrote:
On 01/02/2013 06:43 PM, Jan Kiszka wrote:
Hi,
this may involve some refactoring of the HAL and a bit of I-pipe, so I
better ask first:
Not sure when it changed, but XNARCH_TIMER_IRQ may no longer return the
same values when called on different CPUs. Therefore, It should rather
be called XNARCH_THIS_CPU_TIMER_IRQ now.
Looking at its users (an I-pipe debug warning pointed it out), there are
two that don't expect this: xnintr_query_next() and format_irq_proc().
The former actually wants XNARCH_TIMER_IRQ(cpu), the latter needs
something like is_timer_irq_on_any_cpus(irq).
So I would propose to refactor XNARCH_TIMER_IRQ and RTHAL_TIMER_IRQ
accordingly. But this unfortunately requires extensions of I-pipe to
provide something like __ipipe_hrtimer_irq(cpu) and
__ipipe_this_cpu_hrtimer_irq. And some ugly workaround in Xenomai for
older I-pipe versions.
Does this make sense?
Made something similar for forge:
http://git.xenomai.org/?p=xenomai-gch.git;a=commitdiff;h=37ca257af466e7e5fbfb402b39f088487d048fd5;hp=a9971c363fd361b428f12200536bc5a01dff9c05
Caution, this code is WIP. nktimer will have to move to the percpu
scheduler descriptor to complete this.
That's nkclock in 2.6. Mostly a cosmetic issue, the interrupt name will
not be properly printed, statistics are already per-cpu. Could be
improved nevertheless.
My point is to tell you that what you look to in -forge regarding this
area is in a state of flux. I'm not referring to 2.6, I'm focusing
almost exclusively on 3.x these days.
Is there an easy way to find out if we have per-CPU timers on some arch?
Why should we assume differently?
To avoid dumping redundant statistic lines when some timer IRQ has no
home on a given CPU. But as there are also mixed setups possible as
Gilles pointed out, we need a different approach, likely just skip when
there are no hits.
Your question sounded like "is it possible to know whether an SMP arch
may use different per-CPU IRQs for the timer". I was about to answer
that testing for any pipeline core API rev >= 2 would do, excluding all
legacy patches.
For the cosmetic issue you mention, testing rthal_supported_cpus would do.
Nope, this is not sufficient. A per-CPU timer IRQ would then still
generate useless lines in stat for all those CPUs it is not bound to.
You know which CPU has a real-time timer attached via
rthal_supported_cpus, which timer IRQ # is attached to each real-time
CPU when per-CPU timer IRQs are supported by the pipeline. For legacy
patches which only allow a common IRQ line for all timers regardless of
the CPU, the matter is solved by design. I still don't get where the
issue would be.
I'll resume the work on this as soon as I found the reason for the zero
page corruption we face now with 3.5.
Jan
--
Philippe.
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