Tracking tbench troubles

Posted Oct 30, 2008 11:22 UTC (Thu) by alonso (subscriber, #2828)
Parent article: Tracking tbench troubles

It seems that everything is going slower: ubuntu 8.10 is 20% slower than 7.04 according to phoronix:"There was approximately a 20% drop in performance between 7.04 and 7.10 that remained consistent even in the 8.04 and 8.10 releases."

Tracking tbench troubles

Posted Oct 31, 2008 19:46 UTC (Fri) by njs (guest, #40338) [Link]

Rather odd set of tests. There's clearly something bizarre going on with them; *maybe* gcc has started miscompiling numerics code so badly that every CPU bound test really just takes twice as long, but I would think someone might have noticed that. (The one exception is that apparently the exact same version of GPG got recompiled and went twice as fast, so there's that, I guess.) What can a distro even *do* to kill 50% of your RAM bandwidth, as they measure?

The slowdowns in sqlite might be real -- that's probably fsync-bound, and IO scheduler changes might have affected things.

And finally they conclude that performance has in general dropped off, even though they only measured some odd tasks that most people never wait for anyway. (Exceptions: the game benchmarks, which were flat since they were just benchmarking the ATI drivers anyway, and a tiny GTK+ drawing microbenchmark.) There's a reason that "How long does it take to start OpenOffice" is a more common target for measurement...