[Vm-dev] Profiling and delay accuracy

Andreas Raab andreas.raab at gmx.de
Fri Jun 15 05:43:09 UTC 2007


Hi Tim -

tim Rowledge wrote:
> See the thread on 'primitive timing issues' starting march 16 2004 and 
> other threads around the same time such as 'User interrupts no longer 
> interrupt locked UI process'

Hm ... I don't really remember those discussions and unfortunately 
Google comes up empty when looking for any of the following:

http://www.google.com/search?q=primitive+timing+issues
http://www.google.com/search?q=User+interrupts+no+longer+interrupt+locked+UI+process

Do you by any chance have a pointer to those discussions?

> To quote from my VMMaker 3.7 beta announcement
> "The cumbersome timing of primitives is removed from primitiveResponse 
> since most internal numbered prims are quick. Those that are not use
> #forceInterruptCheck to require an ASAP checkForInterrupts.

With my profiling hat on this decision seems questionable. Even though 
the quick primitives may be quick, once you start profiling you *really* 
want them measured.

But more importantly, even if internal numbered primitves are quick, 
shouldn't at least primitiveExternalCall and primitiveCalloutToFFI to 
have timer checks?

Cheers,
   - Andreas


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