Interesting article. Do you have a link to the article it appears to be a response to?
> Date: Thu, 24 Dec 2015 14:42:19 -0500 > From: [email protected] > Subject: Re: Is there a source for detailed, instruction-level performance > info? > To: [email protected] > > Or as I said in 1974 ... > https://books.google.com/books?id=XrgyMRVh128C&pg=PA16 > > (Gawd, I'm turning into Lynn Wheeler ... <g>) > > Charles > > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:[email protected]] On > Behalf Of Skip Robinson > Sent: Thursday, December 24, 2015 2:27 PM > To: [email protected] > Subject: Re: Is there a source for detailed, instruction-level performance > info? > > This is in no way a personal comment on Tom's experience. > > 'What a programmer is supposed to do' is avoid stupid code. We were once > tasked with finding the bottleneck in a fairly mundane VSAM application. It > ran horribly, consuming scads of both CPU and wall clock. It didn't take > long using an OTS product to discover that for every single I/O, the cluster > was being opened and closed again even though nothing else happened in the > meantime. Simply changing that logic slashed resource utilization. > > In another case, we were on the verge of upgrading a CEC when the > application folks themselves discovered a few grossly inefficient SQL calls. > Fixing those calls dropped overall LPAR utilization dramatically. > > What Tom and I are both saying is that focus on instruction timing should be > seen as more of an avocation than a serious professional pursuit. Like > playing with model trains at the expense of improving actual rail systems. > It's interesting, but not much real business depends on the outcome. > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
