On 28/2/23 13:47, David Crayford wrote:
On 25/2/23 01:23, Farley, Peter wrote:
Python on the mainframe is pretty good, but still can't beat out Rexx
in performance even when the Rex script needs to use BPXWUNIX and
friends to access z/OS Unix file systems,
I have conducted a series of benchtests, and the results suggest that
REXX is not as fast as Python. In my testing, I compare the
performance of C, Lua, Python, and REXX, and the results are clear: C
is the fastest, followed by Lua, which is within an order of magnitude
of C. Python comes next, within an order of magnitude of Lua, and REXX
consistently performs the poorest. In addition to the performance
factor, the vast Python ecosystem compared to the limited options
available for REXX also make it an easy decision. Python is also
simpler to extend with packages, while REXX requires more effort and
potentially complex steps, such as using modern libraries that require
Language Environment (LE).
My benchtests
Lua
local file = assert(io.open(arg[1], "rb, type=record, noseek"))
while true do
local rec = file:read()
if not rec then break end
end
Python
import sys
from pyzfile import *
try:
with ZFile(sys.argv[1], "rb,type=record,noseek") as file:
for rec in file:
pass
except ZFileError as e:
print(e)
REXX
/* REXX */
arg dsname
address MVS
call bpxwdyn "ALLOC FI(INPUT) DA("dsname") SHR"
do until eof
"EXECIO 10000 DISKR INPUT ( STEM rec."
eof = (rc > 0)
end
"EXECIO 0 DISKR INPUT ( FINIS"
The results: Add user+system to get total CPU time
> time lua benchio.lua "//'CPA000.QADATA.PMR99999.SSA.HR1315PM'" &&
time python3 benchio.py "//'CPA000.QADATA.PMR99999.SSA.HR1315PM'" &&
time ./benchio.rex "CPA000.QADATA.PMR99999.SSA.HR1315PM"
real 0m47.019s
user 0m3.255s
sys 0m1.097s
real 1m0.710s
user 0m8.001s
sys 0m2.678s
real 1m17.772s
user 0m13.575s
sys 0m4.536s
----------------------------------------------------------------------
For IBM-MAIN subscribe / signoff / archive access instructions,
send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
