Re: [tor-relays] big spike in cpu usage

On Fri, 5 Apr 2013 13:50:29 -0400 Owen Gunden ogunden@phauna.org wrote:

This worked fine until recently. However, just today I noticed the machine was sluggish, and sure enough tor was using 99% cpu and dumping these messages to syslog:

You can check if your host has throttled/limited your total CPU usage.

I like this completely unscientific quick test that doesn't require installing any extra software:

dd if=/dev/zero bs=1M count=1024 | md5sum

Should return 250-400 MB/sec on a modern CPU.

Check if you get significantly less. E.g. on one host I had about 80-100 MB only, despite /proc/cpuinfo and the like all showing normal CPU frequencies, so couldn't tell there was any throttling other than from testing.