Using a file to store the variables a while, uggghhh... File I/O remains terribly slow compared to memory access, even though you might save some CPU (I don't know if you will save) the result may be code than takes longer to complete in elapsed time.
The fact that EXECIO is faster than PIPE to write files is that one often sees execs that every now and then write to a file. If you do that with PIPE, the file is closed after each write request; with EXECIO, the file is only closed when you explicitly ask for it. Again, the general rule is: do as much as possible in a single call, to PIPE, to XEDIt, to .... 2007/1/12, [EMAIL PROTECTED] <[EMAIL PROTECTED]>:
From my testing, PIPES incur quite a bit of overhead when starting up. So, optimising means doing as much as possible within a PIPE to amortise that overhead over as much work as possible, and therefore using as few PIPE instances as possible. You could write the variables to a temporary disk file as well. But use EXECIO instead of PIPES to write the file, it uses less resources for small files. -----Original Message----- From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On Behalf Of Peter Rothman Sent: January 12, 2007 10:55 To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Rexx performance question Tested that - also much slower than GLOBALV. Kris Buelens <[EMAIL PROTECTED] il.com> To Sent by: The IBM IBMVM@LISTSERV.UARK.EDU z/VM Operating cc System <[EMAIL PROTECTED] Subject ARK.EDU> Re: Rexx performance question 01/12/2007 10:23 AM Please respond to The IBM z/VM Operating System <[EMAIL PROTECTED] ARK.EDU> Have you tried this too? PIPE LITERAL VAR1 VAR2 VAR3 ...| SPLIT |VARFETCH 1 DIRECT TOLOAD|VARLOAD DIRECT Note: the "DIRECT" tells not to try to resolve compound symbols, this also means one must pass the variable names in uppercase (and stem suffixes in the exact case). -- Kris Buelens, IBM Belgium, VM customer support 2007/1/12, Peter Rothman <[EMAIL PROTECTED]>: We have an old REXX exec that I had to modify. This is a rather simplistic description but it consists of 2 parts - 1 to set up the environment(variables) and 2 to use the variables setup in 1. Bottom I had problems modifying it so I re-wrote it. The original used GLOBALV extensively - part 1 would do PUTs and part 2 would do GETs. Besides a lot of 'steam lining' I thought I would be 'clever' and changed the GLOBALVs to 'PIPE var VarName 1 | var VarName'. However the new exec ran much slower than the old. I then did a test to only compare GLOBALV PUT/GET to setting and retrieving the variable with PIPE var stage. The pipe stage was much slower. I thought the pipe logic would be better - obviously mistaken. Any comments - any other method I could have used that is perhaps faster than GLOBALV? Thanks Peter The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review retransmission dissemination or other use of or taking of any action in reliance upon this information by persons or entities other than the intended recipient or delegate is strictly prohibited. If you received this in error please contact the sender and delete the material from any computer. The integrity and security of this message cannot by guaranteed on the Internet. The Sender accepts no liability for the content of this e-mail or for the consequences of any actions taken on basis of the information provided. The recipient should check this e-mail and any attachments for the presence of viruses. The sender accepts no liability for any damage caused by any virus transmitted by this e-mail. This disclaimer is the property of the TTC and must not be altered or circumvented in any manner.
-- Kris Buelens, IBM Belgium, VM customer support
