>Later versions of AIX have two larger page sizes available and so the >number of locks to be taken and released drops dramatically for the >typical 256KB tape transfer.
This is what I'm really confused about, and our AIX admins don't have an answer. Our Power systems with AIX supports 4k, 64k and 16mb pages. The IBM presentation makes the case about minimizing lock contation b using 16mb non-pagable pages. But it also notes that using 64k pages can greatly minimize the contention. When I check svmon, most of our BSS heap segments are already using both small(4k) and medium(64k) pages (the "sm" in the listing below). svmon -P 10944554 | grep -i "bss heap" d811d8 12 work text data BSS heap sm 57518 0 0 57518 ab892b 13 work text data BSS heap sm 48006 0 0 48006 f8317a 14 work text data BSS heap sm 37204 0 0 37204 bc0f3c 11 work text data BSS heap sm 34200 0 0 34200 f50e75 10 clnt text data BSS heap, s 28667 0 - - 991d9b 15 work text data BSS heap sm 26213 0 0 26213 9e279c 16 work text data BSS heap sm 9023 0 0 9023 92d013 17 work text data BSS heap sm 3652 0 0 3652 I don't see any way to tell if the I/O is locking 4k pages, 64k pages, or a mix. The presentation gave 2 different LDR_CNTRL variables depending upon if you want 16mb pages or 64k pages. 16mb pages: LDR_CNTRL=TEXTPSIZE=64K@STACKPSIZE=64K@SHMPSIZE=64K@LARGE_PAGE_DATA=Y dsmserv 64k pages: LDR_CNTRL=TEXTPSIZE=64K@STACKPSIZE=64K@SHMPSIZE=64K@DATAPSIZE=64K dsmserv My assumption is that the 64k LDR_CNTRL will make all the BSS heaps use only 64k pages. I'm tempted to try this first since it doesn't require an AIX reboot, just a TSM shutdown/startup. Rick ----------------------------------------- The information contained in this message is intended only for the personal and confidential use of the recipient(s) named above. If the reader of this message is not the intended recipient or an agent responsible for delivering it to the intended recipient, you are hereby notified that you have received this document in error and that any review, dissemination, distribution, or copying of this message is strictly prohibited. If you have received this communication in error, please notify us immediately, and delete the original message.