RE: Latency traces I cannot interpret (sa1100, 2.6.15-rc7-rt1)

["kus Kusche Klaus" <kus@keba.com>]

> From: Ingo Molnar
> * Lee Revell <rlrevell@joe-job.com> wrote:
> > > However, traces 1, 2, 6 and 7 are completely mysterious to me.
> > > Interrupts seem to be blocked for milliseconds, while 
> nothing is going
> > > on on the system? Moreover, there are console-related 
> function names
> > > in
> > > traces 6 and 7, although I've unconfigured the 
> framebuffer console for
> > > these runs!
> > 
> > It seems that either some code path really is forgetting to 
> re-enable 
> > interrupts, or there's a bug in the latency tracer.
> 
> one question is, what do the kernel addresses visible in the first 
> argument of asm_do_IRQ() correspond to:
> 
>  trace1:MyThread-153   0D..1 5977us+: asm_do_IRQ (c030c170 1a 0)
>  trace1:MyThread-153   0D..1 15191us+: asm_do_IRQ (c030c1bc 1a 0)
>  trace2:  <idle>-0     0D..2 8822us+: asm_do_IRQ (c021da24 1a 0)
>  trace2:  <idle>-0     0Dn.2 8920us+: asm_do_IRQ (c021da24 b 0)
>  trace3:     top-169   0D..1 8802us+: asm_do_IRQ (c024e5fc 1a 0)
>  trace4:  insmod-185   0D..1 8794us+: asm_do_IRQ (c030c174 1a 0)
>  trace5:      dd-197   0D..1 8812us+: asm_do_IRQ (c02e4938 1a 0)
>  trace6: kthread-11    0d..3 2670us+: asm_do_IRQ (c02fe2d0 1a 0)
>  trace7:MyThread-95    0D..1  542us+: asm_do_IRQ (c02fe2d0 1a 0)
>  trace7:MyThread-95    0D..1 9755us+: asm_do_IRQ (c02fe2d0 1a 0)
> 
> i.e. what is c02fe2d0, c021da24, c02e4938, etc.?

I do not have that kernel or configuration any longer,
so I cannot look those addresses up.

I recreated a similar kernel, did similar experiments, got
similar traces, looked up the new addresses.

The one in the "<idle>-0" trace is "cpu_idle".

The others I got were mostly related to the load on the system,
all over the kernel:
Floating point emulator (call_fpe, float64_to_float32, ...),
jffs2 (deflate_fast, ...), console write (several places within
sa1100_console_write).

The strange ones in my new experiments were "mcount" and
"notify_die".

Do you need more of them?

-- 
Klaus Kusche                 (Software Development - Control Systems)
KEBA AG             Gewerbepark Urfahr, A-4041 Linz, Austria (Europe)
Tel: +43 / 732 / 7090-3120                 Fax: +43 / 732 / 7090-6301
E-Mail: kus@keba.com                                WWW: www.keba.com
 
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