-----Original Message----- From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf Of Kelly Arrey Sent: Thursday, June 04, 2009 3:07 PM To: IBM-MAIN@bama.ua.edu Subject: Re: Why are z/OS people reluctant to use z/OS UNIX?
> >Also those of us who compile using the C/C++ compiler in USS need a lot of > >memory because the compiler is a memory hog when optimizing. It's no > >different when compiling using batch. > Not to mention a cpu hog. It's true, our compiler can take up a lot of memory and cpu. We provide several choices of optimization levels, and a highly optimized application can use significantly less cpu than an unoptimized app. The IPA level of optimization, for example, does whole program optimization, which exposes many more optimization opportunities than optimizing one source file at a time. However, optimizing an entire program requires significantly more memory, and cpu. One of the ways we have tried to mitigate this is to move memory used by the IPA compile phase "above the bar", i.e., into 64-bit virtual storage. Considering the number of times the application code will be executed in production, the cpu time invested in optimizing it can be time well spent. <SNIP> How much memory does the PL/1 (optimizing) compiler take? Are there any lessons that can be learned and applied? Regards, Steve Thompson -- Opinions expressed by this poster may not reflect those of poster's employer -- ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
