speed problems with Clipper 5.3b linked with blinker 7.0

[Msilver2]

Hello.
I try to keep some Clipper legacy applications on the market, and I try to use Clipper 5.3b and blinker 7 for link.

It works well, but for some reason it runs slower like those compiled with Clipper V 5.01 and linked with Rtlink or Clipper V 5.3b and linked with Exospace.

Of course I made protected mode applications and I made my tests on WinXp and Linux with Dosemu.

Has sombody any idea ?

 

[TonHu]

What's the speed-reduction (percentage) in these situations?
Is the app I/O intensive, Screen intensive or CPU intensive?

TIA
TonHu

 

[Msilver2]

I made a lot of tests, I suppose of evry kind:
- a simple loop with macrooperations (&) inside, with INKEY() or without,
- a complex application with a lot of screen operation,

In evry case there are speed problems.
If I use Inkey() inside in a loop the application lose speed.

The percentage of course depends on the aplication, but some times become two or indeed
three times slower like simple Clipper V 5.01 linked with Rtlink.

I know from blinker help: "programs running under a DOS extender which heavily access DOS,
the BIOS or other external resources will often be continually switching between real and
protected mode, so may run slower than in real mode",
and: "This is extremely program dependent",
but finally it seems to me there is an overall speed problem.

 

[TonHu]

May I suggest (I seem to do this more often as time passes by) to have a look at xHarbour (

http://www.xharbour.org

for an open-source and

http://www,xharbour.com

for the same but commercially supported), a Clipper compatible but extended compiler. It also gets your apps complied on most flavors of Linux, OS/2 and Mac OS X.
It will take a little time to setup right (the open-source version I mean) but I think it's really worth the efford.

The part on the context switching for Blinker, and Protected mode in general, could be the real culprit here, I'd have liked some real figures to see the actual slowdown in numbers. I have no pointers on how to improve it though, so don't bother for now.

Screenoutput is heavily crippling app-speed during any display if you don't turn off the cursor, but this has been true from Clipper A'85 AFAIK. Could be worse as well on PM-mode. It could be worth re-testing this part?

HTH
TonHu