Arkanoid: "Sleep 10" to reduce CPU usage

[ErosOlmi]

You will not bealive it.

I changed my Power Basic IDLE message pump (executed during WHILE/WEND operations) from:
[code=thinbasic]
MACRO NewDoEvents
MacroTemp nde_Msg
Dim nde_Msg As TagMsg
If PeekMessage(nde_Msg, %Null, 0, 0, %PM_REMOVE) Then
TranslateMessage nde_Msg
DispatchMessage nde_Msg
End If
END MACRO

[/code]

to

[code=thinbasic]
MACRO NewDoEvents
'GLOBAL nde_Msg AS TagMsg
MacroTemp nde_Msg
Dim nde_Msg As TagMsg
If PeekMessage(nde_Msg, %Null, 0, 0, %PM_REMOVE) <> 0& Then
If nde_Msg.message = %WM_QUIT Then
Else
TranslateMessage nde_Msg
DispatchMessage nde_Msg
End If
End If
END MACRO
[/code]

I think the change that effect CPU is from:
[code=thinbasic] If PeekMessage(nde_Msg, %Null, 0, 0, %PM_REMOVE) Then[/code]
to
[code=thinbasic] If PeekMessage(nde_Msg, %Null, 0, 0, %PM_REMOVE) <> 0& Then[/code]

I will investigate further about this.

Ciao
Eros

[Petr Schreiber]

Incredible ,


how did you found that ... I have no idea
But fact is that it works!


Perfect,
Petr

[ErosOlmi]

I Google http://www.google.com/search?hl=en&q=apisleep+function
And on the second link reported by Google I found this post: http://www.powerbasic.com/support/pb...ad.php?t=11924
In there Michael Ritter reported a loop very similar to mine but with "<> 0&" boolean test. I tried and voilla, the magic.
_________________________________________________

On my Core Duo, CPU usage drop from fixed 50% (mainly one processor always 100% CPU) to 15-25 % variable CPU usage.

I confirm the effect is done by the test
<> 0&
instead of not logic comparison test.

I need some more confirmations because I have a lot of boolean tests made with just: IF variable THEN
Worth and investigation.

Eros

[Petr Schreiber]

I thought those tests are 100% equivalent,

good to know that they are not!
I have to go offline now or I will become zombie, but tommorow I will do some benchmarks ... very interesting.


Petr

[ErosOlmi]

Hold on.

I would like to give a kick in my back. I introduced a big mistake in the posted thinCore.dll version (now removed).
Reduction of CPU usage was due to a time slice I reserved to the OS adding an internal looper I left by mistake.
But with this looper, WHILE loops are too much slow.

I'm reconsidering the entire matter.
Maybe a sleep somewhere or better a new keyword that give some time to the OS is better.

Sorry for the above ... illusion.

[ErosOlmi]

I think I've got a good compromise.

Instead of adding an internal SLEEP that would influence all scripts and (worst) it would be something "imposed" by the engine, I've modified DOEVENTS keyword in such a way that, if executed, it will give some time slice to the OS reducing CPU usage.

So, download attached file and to see results, just add a DOEVENTS inside the main loop of the script or where you think it would be better to give time to CPU.

Regards
Eros

[Petr Schreiber]

Hi Eros,

I tried to use it like:
[code=thinbasic]
while tbgl_IsWindow(hWnd)
doevents
...
wend
[/code]

... and it seems to work very nicely. Even with this "slowdowner" it is possible to reach framerates exceeding refreshrate of LCD while CPU is at nice 0-10%. Good job done, no need for kicking yourself


Petr