Description of BENCH
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From Kris Buelens, IBM Belgium
BENCH makes it easy to check how much CPU, I/O and paging a command costs. It also allows to easily compare the consumption of two alternative implementations of a command (e.g. PIPE <-> EXECIO )
A very short example:
Let's see how much ASSEMBLE of a small program costs:
bench assemble cmpa ASSEMBLER (XF) DONE NO STATEMENTS FLAGGED IN THIS ASSEMBLY results of: 1 time(s) assemble cmpa Virtual cpu time : 0.45 Sec = 00:00:00.45 Total cpu time : 0.52 Sec = 00:00:00.52 Start I/O : 57 IO time (.025 per IO): 1.43 Sec = 00:00:01.43 Elapsed time : 1.67 Sec = 00:00:01.67 Service time (IO+CPU) : 1.95 Sec = 00:00:01.95 Page reads : 0 Page writes : 0 Ready;We know for example that 57 IO's were required and that .52 seconds CPU were consumed. These data come from comparing the result of an IND USER and Q TIME before and after the command. The IO time is a wild guess, we suppose each IO costs 25 miliseconds.
Now let's see if it is true that HLASM is better than ASSEMBLE:
bench (run next) hlasm cmpa RDR FILE 7716 SENT FROM BUELENSC PUN WAS 7716 RECS 0149 CPY 001 A NOHOLD NOKEEP results of: 1 1 X : assemble cmpa (rc=0) 2 1 X : hlasm cmpa (rc=0) R V.cpu T.cpu SIO IO Service Elapsed Page Page | Comment/Command U time time time time time rds wrts | N (Secs) (Secs) nbr (Secs) (Secs) (Secs) | --------------------------------------------------------+---------------------- 1 0.45 0.52 57 1.43 1.95 1.67 0 0 assemble cmpa 2 0.36 0.40 40 1.00 1.40 1.24 0 5 hlasm cmpa Ready;We can indeed conclude that this is the case.
REXX coders can use BENCH to compare different incantations of an EXEC. Refer to BENCH HELPCMS for an example highlighting that address command performs better than the default of address CMS
BENCH 1.1 (28 Nov 1997)
Avoid a REXX syntax error when calling BENCH2 LAST without having BENCH2 INIT
BENCH 1.2 (17 Jun 1999, 2 Jun 2003)
CPU consumption is expressed with a higher precision: we use Diagnose 0C instead of CP Q TIME.