I am with Bernd on the Rexx I/O has been a bottleneck, but logically speaking
I/O can be a bottleneck being slow than memory functions. My Rexx experience is
with VM, Netview, TSO, z/OS. Also Orexx on Linux and Windows. So I speak from
experience as I am sure Bernd does.
Scott ford
www.identityforge.com
from my IPAD
> On Oct 23, 2014, at 10:08 PM, David Crayford <dcrayf...@gmail.com> wrote:
>
>> 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.
>
>> 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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