bpxwunix does a spawn() of /bin/sh. If you pass the env var _BPX_SHAREAS=YES a local spawn is done. Address syscall should be far more efficient than running a shell command that gives something similar, not to even mention parsing the output. A quick experiment on our development system shows 'readdir pathname dir. attr.' is about 17X faster than bpxwunix 'ls -l pathname',,'dir.' and ls is a builtin. Trying a non-builtin on a small file, readfile is giving me about 2200X faster than head. Using _BPX_SHAREAS=YES, ls -l stays about the same and readfile is about 1600X faster than head.
Bill Schoen > > Date: Thu, 12 Dec 2019 11:44:25 -0600 > From: Kirk Wolf <[email protected]> > Subject: Re: OMVS Tuning ? > > I have a related question, maybe someone who is more familiar with > bpxwunix() knows - does it do a spawn() or a fork()/exec() under the > covers? If spawn(), is it possible to do a local spawn? The doc that I > see is silent. > > I'm also not a REXX expert, but what about running your REXX ISPF dialog > with syscalls('ON') and then using the REXX syscalls directly? > Could you use the spawn()/spawnp() syscall with a "local spawn"? Then, > you will only be dubbing once (at syscalls('ON')), and you wouldn't be > starting a new OMVS address spaces. > > I know that you can have an ISPF dialog program written in C/C++ that uses > the C library to do Unix stuff: the first thing that does a UNIX syscall > will dub the address space. You can use (local) spawn to invoke other > commands in child processes but in the same address space. We've done > this before and it works well. > > On the other hand, maybe your performance problem is something specific to > your dev system, and otherwise not really significant? Try posting a tiny > REXX test case and maybe others on the list will see what kind of > performance they get. > > Kirk Wolf > Dovetailed Technologies > https://urldefense.proofpoint.com/v2/url? > u=http-3A__dovetail.com&d=DwIFaQ&c=jf_iaSHvJObTbx-siA1ZOg&r=rFsK2G- > kj0QZo0UhxA9XKA&m=lbGfjbkv3Q2gb_9r2CrFg7iehrvchvT2AdhVuuMZPzc&s=8rrtkhpUfcLuQibwRUqnAjcMV0ZsTCjkGoB1ticrOaA&e= > > On Thu, Dec 12, 2019 at 6:07 AM Lionel B Dyck <[email protected]> wrote: > > > Thanks for the update on STEPLIB - I didn't see it in 2.1 but my search > > may have been using the wrong keywords. > > > > I did some testing doing bpxwunix from rexx. 1 test was issuing the env > > command and the other a cd followed by an ls -la. > > > > With libraries in STEPLIB and in ISPLLIB the timing on my system (which is > > a z/VM guest) was 10 and 4 seconds respectively under ISPF and 4 and 2 > > seconds in native TSO. This pointed to the ISPLLIB as a tasklib so I > > removed everything from it and the timing under ISPF went from 10 down to 7 > > seconds and 4 to 1 seconds. Removing the STEPLIB got me to 2 and 0.5 > > seconds. > > > > Still not subsecond so I suspect there is something in the z/VM setup > > which I'm not sure how to diagnose but am looking. > > > > Thanks > > > > > > Lionel B. Dyck <sdg>< > > Website: https://urldefense.proofpoint.com/v2/url? > u=http-3A__www.lbdsoftware.com&d=DwIFaQ&c=jf_iaSHvJObTbx- > siA1ZOg&r=rFsK2G- > kj0QZo0UhxA9XKA&m=lbGfjbkv3Q2gb_9r2CrFg7iehrvchvT2AdhVuuMZPzc&s=7tuhSdThQv_b82yhdAYgJk0cPl2I0hp5M2-0XQ44oWU&e= > > > > "Worry more about your character than your reputation. Character is what > > you are, reputation merely what others think you are." - John Wooden > > > > -----Original Message----- > > From: IBM Mainframe Discussion List <[email protected]> On Behalf > > Of Kirk Wolf > > Sent: Wednesday, December 11, 2019 7:20 PM > > To: [email protected] > > Subject: Re: OMVS Tuning ? > > > > Lionel, > > > > STEPLIB=none has been around for a long time, and I see it documented, for > > example, in the V1R13 z/OS UNIX Planning book. > > > > Can you offer any more details as to where the performance is bad or how > > you notice? I would assume that what you are describing is something > > relative to the time required to do a fork/exec or spawn. Which? local > > spawn? > > > > On Wed, Dec 11, 2019 at 2:04 PM Lionel B Dyck <[email protected]> wrote: > > > > > Found one major issue - the systems where the issue is are z/OS 2.1 > > > and the STEPLIB=none variable looks to have been new in 2.2. Reducing > > > the STEPLIB and ISPLLIB solved things. > > > > > > > > > Lionel B. Dyck <sdg>< > > > Website: https://urldefense.proofpoint.com/v2/url? > u=http-3A__www.lbdsoftware.com&d=DwIFaQ&c=jf_iaSHvJObTbx- > siA1ZOg&r=rFsK2G- > kj0QZo0UhxA9XKA&m=lbGfjbkv3Q2gb_9r2CrFg7iehrvchvT2AdhVuuMZPzc&s=7tuhSdThQv_b82yhdAYgJk0cPl2I0hp5M2-0XQ44oWU&e= > > > > > > "Worry more about your character than your reputation. Character is > > > what you are, reputation merely what others think you are." - John > > > Wooden > > > > > > -----Original Message----- > > > From: IBM Mainframe Discussion List <[email protected]> On > > > Behalf Of Lionel B Dyck > > > Sent: Wednesday, December 11, 2019 12:58 PM > > > To: [email protected] > > > Subject: OMVS Tuning ? > > > > > > I am working on a project where the omvs performance on some systems > > > is slower than one would like -definitely not sub-second. > > > > > > > > > > > > I'm looking for tuning suggestions. > > > > > > > > > > > > When under ISPF the elapsed time is more than double the elapsed time > > > when in native TSO. > > > > > > > > > > > > Note that the OMVS environment includes STEPLIB=none but my guess is > > > that the ISPLLIB may be the culprit when under ISPF - I just can't > > > prove that (yet). > > > > > > > > > > > > Thanks for any guidance. > > > > > > > > > > > > > > > > > > Lionel B. Dyck <sdg>< > > > Website: <https://urldefense.proofpoint.com/v2/url? > u=http-3A__www.lbdsoftware.com_&d=DwIFaQ&c=jf_iaSHvJObTbx- > siA1ZOg&r=rFsK2G- > kj0QZo0UhxA9XKA&m=lbGfjbkv3Q2gb_9r2CrFg7iehrvchvT2AdhVuuMZPzc&s=ltyuZpKNwSpNExe-7RTeZ8HQj5a4b642JlbYuNkLQxc&e= > > https://urldefense.proofpoint.com/v2/url? > u=http-3A__www.lbdsoftware.com&d=DwIFaQ&c=jf_iaSHvJObTbx- > siA1ZOg&r=rFsK2G- > kj0QZo0UhxA9XKA&m=lbGfjbkv3Q2gb_9r2CrFg7iehrvchvT2AdhVuuMZPzc&s=7tuhSdThQv_b82yhdAYgJk0cPl2I0hp5M2-0XQ44oWU&e= > > > > > > "Worry more about your character than your reputation. Character is > > > what you are, reputation merely what others think you are." - John > > > Wooden > > > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
