Re: profiling connection overhead
Tom Lane <tgl@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Jeff Janes <jeff.janes@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, Robert Haas <robertmhaas@gmail.com>, Bruce Momjian <bruce@momjian.us>, pgsql-hackers@postgresql.org, Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
Date: 2010-11-29T18:10:07Z
Lists: pgsql-hackers
Jeff Janes <jeff.janes@gmail.com> writes: > Are you sure you haven't just moved the page-fault time to a part of > the code where it still exists, but just isn't being captured and > reported? I'm a bit suspicious about that too. Another thing to keep in mind is that Robert's original program doesn't guarantee that the char array is maxaligned; though reasonable implementations of memset should be able to use the same inner loop anyway for most of the array. I did some experimentation here and couldn't find any real difference in runtime between the original program and substituting a malloc() call for the static array allocation. Rolling in calloc in place of malloc/memset made no particular difference either, which says that Fedora 13's glibc does not have any optimization for that case as I'd hoped. regards, tom lane