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Re: Using instrument buffer by applications?
On 2008-07-21, Andrew Lunn <andrew@lunn.ch> wrote:
>> Has anybody used the instrument buffer scheme to log
>> application events?
>
> I have, but my events were over a short period of time.
For my apps, there are going to be bursts of a few events
separated by gaps that are pretty large (on the scale of the
HAL counter).
> Interestingly, if you look in
> packages/kernel/current/src/instrmnt/meminst.cxx you will
> find:
>
> #ifdef CYGVAR_KERNEL_COUNTERS_CLOCK
> // p->timestamp = Cyg_Clock::real_time_clock->current_value_lo();
> HAL_CLOCK_READ( &p->timestamp );
> #else
> p->timestamp = 0;
> #endif
>
> so it looks like you can change from HW ticks to slower eCos
> timer ticks.
I saw that, but assumed it would break other stuff if I changed
it. I thought about adding aonther field so that it recorded
both the low 32 bits of the system tick counter and the value
from HAL_CLOCK_READ(). That would get me a rollover at about 3
(1ms) or 30 years (10ms), but I'd still have a resolution of
about 25ns.
years with
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