Steel Bank Common Lisp

Benjamin Lambert <benlambert@...> writes:
> Is there any documentation available that describes what the report  
> from sb-sprof means? The main thing I'm confused about is what are  
> the differences among "self", "cumul", and "total".

No, it's not documented. One reason is that I keep wondering whether
"cumul" and "total" should be switched around, which we really
shouldn't do once they've been formally documented.

"self" is time spent executing the function itself. "cumul" is the
time spent in the function or functions called from it. "total" is the
sum of the "self"s of this function, and all functions above it in the
list.

Or maybe "cumul" and "total" were the other way around. I
forget... ;-) It should be obvious from the report which is which.

> But also I wonder exactly what the profiler samples.  Does it just
> sample the function that is currently executing or does it sample
> the entire call stack?

Neither. By default it samples eight levels of the call stack on x86
and x86-64, and two levels on other platforms.

-- 
Juho Snellman

On Jul 18, 2006, at 7:23 PM, Juho Snellman wrote:

>> But also I wonder exactly what the profiler samples.  Does it just
>> sample the function that is currently executing or does it sample
>> the entire call stack?
>
> Neither. By default it samples eight levels of the call stack on x86
> and x86-64, and two levels on other platforms.

Thanks Juho.  Just one more question, if 8 and 2 are the defaults for  
this, is it possible to increase them?  Or are there hard limitations  
on how far back in the stack it's possible to look when sampling?

Ben

Ben Lambert <belambert@...> writes:

> On Jul 18, 2006, at 7:23 PM, Juho Snellman wrote:
> 
> >> But also I wonder exactly what the profiler samples.  Does it just
> >> sample the function that is currently executing or does it sample
> >> the entire call stack?
> >
> > Neither. By default it samples eight levels of the call stack on x86
> > and x86-64, and two levels on other platforms.
> 
> Thanks Juho.  Just one more question, if 8 and 2 are the defaults for
> this, is it possible to increase them?  Or are there hard limitations
> on how far back in the stack it's possible to look when sampling?

You can increase it on x86* by increasing the value of +sample-size+
and recompiling sb-sprof. There's no hard limit, but profiling will
cause bigger slowdowns with higher depths. For non-x86oid platforms
going beyond 2 levels would require some coding.

-- 
Juho Snellman