> -----Original Message-----
> From: IBM Mainframe Discussion List On Behalf Of David Crayford
>
> On 24/10/2014 6:50 AM, Bernd Oppolzer wrote:
> > Doesn't the example in the benchmark show performance problems in
> > EXECIO instead of REXX? EXECIO, IMO, is not part of the REXX
> > interpreter, but instead it is a vehicle (an external function) to do
> > I/O from REXX on z/OS.
> > Other REXX implementations
> > (for example, on Linux or Windows) don't use EXECIO etc.; I/O there is
> > done with native REXX functions.
> >
>
> I don't want to be too disparaging about REXX but I've profiled it
> extensively and it is not an effecient implementation. The variable
> access routines are where it spends a lot of time so any address SUBCOM
> interface is slow
> when compared to fast scripting languages. Compiled REXX has a serious
> flaw in it's memory management. I profiled it using IBM APA and it
> appears to do a GETMAIN every time it wants a new stem varaible element.
> It could be dramatically improved just be using a better storage
> manager. I would want my money back if I paid for the REXX compiler.
>
> > So to be fair, the REXX interpreter functions should be compared with Lua
> > interpreter functions, for example: some loop control or arithmetic.
> > Compiled languages like C will always outperform interpreted languages
> > in this area, so such comparisons are only of academic interest.
> >
>
> Lua is written in C and the majority of it's libraries are too. In some
> cases there is only 10% overhead for the Lua VM. I've got an SQL
> bench-test where Lua is not too far off C. And much easier to code and
> maintain.
>
> OK, let's try simple matrix multiplication which should test both array
> access and math.
>
> /* REXX */
> arg count
> if count = "" then count = 1000000
> start = sysvar("SYSCPU")
> do i = 1 to count
> a.i = i * i
> end
> say 'CPU time = 'sysvar("SYSCPU") - start
>
> CPU time = 3.57
>
> local t = require("timer")()
> local count = arg[1] or 1000000
> local a = {}
> for i = 1, count do a[i] = a[i] * i end
> t:print_elapsed()
>
> elapsed time: 0.131965
>
>
> That's a huge difference, two orders of magnitude.
But remember that IBM also sells hardware...... :-)
-jc-
>
> > Kind regards
> >
> > Bernd
> >
> >
> >
> > Am 24.10.2014 00:24, schrieb Shane Ginnane:
> >> Good one Dave, glad you were able to convince your "powers that be"
> >> to get this out the door.
> >> Let's hope it gets some acceptance.
> >>
> >>> Now you have Lua installed why don't you bench-test it against REXX and
> >>> report if you get similar results to what I get on my machine
> >> Now don't you go training everybody out there as to what a slug REXX
> >> really is ... ;-)
> >>
> >> Shane ...
> >>
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