[Vm-dev] OS X Mavericks & cog tickers

John McIntosh johnmci at smalltalkconsulting.com
Thu Oct 24 23:25:49 UTC 2013

Must not hit enter...

may or may not one has to find the actual code and maybe it is platform
dependent etc etc.

An attempt was made to ask the VM what the next wakeup time is. The VM
actually knows this it's the bottom end of the Delay logic.
We then sleep to this tick, using a call that should awake the process if
an BSD interrupt (ill defined) arrives.

In here we also service socket handles etc and oh maybe some other house

Still the objective was to sleep until we have to wake up for Morphics 50
times a second poll, or some UI/socket/interrupt arrives.

In practice there are some artifacts like the Scheduler saying go to sleep
but awake -2 milliseconds ago because of some race condition with in the
Delay logic. (good luck finding that)...

On Thu, Oct 24, 2013 at 7:18 PM, John McIntosh <
johnmci at smalltalkconsulting.com> wrote:

> Well let me reflect.
> Nothing has changed, the VM energy sapping field is the same as
>  yesterday, just more evident.
>  I wasn't able to determine what code base is used, but if I go back 5 or
> 10 years.
> (a) The morphic event polling cycle runs 50 times a second. One could
> write some timer consolidation code there to consider when do I have to
> wake up and paint all those morphs? No C/Objective-C/assembler/fortran
> required...
> (b) Maybe the VMs are event driven now and Morphic does not need to poll
> 50 times a second?
> (c) The BSD Unix socket system requires polling of some form.  But see
> work by Craig 10-15 back on "Flow"
> (d) When all the Smalltalk Processes settle, the dispatcher runs the
> lowest priority task which calls relinquishProcessorForMicroseconds with
> a bogus value.
> On Thu, Oct 24, 2013 at 6:21 PM, tim Rowledge <tim at rowledge.org> wrote:
>> Looking through some of the low-level changes in Mavericks I noticed
>> stuff about timer consolidation. I *think* that it is something that you
>> can offer to allow, rather than something done unto you code, but almost
>> certainly it will have some sort of impact on the heartbeat ticker type of
>> code used in stackvm/cog. Where is a skilled Mac vm maintainer when you
>> need one?
>> tim
>> --
>> tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
>> "bOtHeR" said Pooh, mistaking the LSD tablet for aspirin
> --
> ===========================================================================
> John M. McIntosh <johnmci at smalltalkconsulting.com>
> Corporate Smalltalk Consulting Ltd. Twitter: squeaker68882
> ===========================================================================

John M. McIntosh <johnmci at smalltalkconsulting.com>
Corporate Smalltalk Consulting Ltd. Twitter: squeaker68882
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