On Thu, 18 Jun 2020 08:52:52 +1000, Andrew Rowley wrote: >On 18/06/2020 1:43 am, Paul Gilmartin wrote: >>> (Concerning preallocating the PDS): >> >> I'm mystified that it made a difference since Lionel never used the allocate >> "dd" in the call to "cp". Only SVC 99 knows. > >I was doing some testing on this last week. The overhead appears to be >obtaining and freeing the enqueue on the PDS for each member. If you >already have a SHR enqueue this is bypassed. The cp command needs to run >in the same address space that obtained the enqueue. > Aha! Highly plausible explanation.
If it improves performance significantly, should it be incorporated into "cp"? RFE? Or documented in a Usage Note? RCF? -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
