zen.org Communal Weblog

There was a grad student here that wrote a Perl program to compute the Jaccard coefficent of some Blast data. The Mac he was using has 8G of memory, but come to about 2GB of memory usage Perl would crash. I reworte it into two programs, first to dump all his data to a gdbm file, then processed that file using the Jaccard coefficent. It never used more then 2G and finished, it took like a day longer to run but we got what we wanted. This all happened a few months ago, and for this and other reasons we moved that project to Solaris.

A few days ago one of our sysadmin was investigating a complaint on why Perl on MacOS X was slow. He built the same Perl twice, one using the system’s malloc(3), the other using the malloc shipped with Perl. Using the original program computing Jaccard coefficent, with a small dataset, it used 1,220 CPU seconds with Apple’s malloc, but only 605 CPU seconds with Perl’s! I asked him to run it with the full data set. Apple’s malloc crashed after 116,700 CPU seconds and ~2.3GB of memory. With Perl’s malloc it used 65,469 CPU seconds and finished after using ~2.8GB of memory.

So happy SysAdminDay!

When Brendan was at Widener he got himself a television.  When he moved to the Bay Area he left it.  Ever since then I’ve had it, and it’s been getten worse and worse.  The tuner has always been fine but the picture has been getting smaller and smaller.  Somebody once told me that if you don’t mind putting a solder gun to it you can replace the broken chip.  I put it out on the curve last night.

Up came waltzing a black man, he picked it up and shook it.  Across the street stood an old truck with a latin man waiting in the cab.  Off they drove with Brendan’s television.  I’d like to think it’s life has just begun.