I've finally gotten around to trying out DTrace, and I have to say thatit actually is pretty cool so far. I haven't used it on kernel sidestuff, just to poke at user programs, for which it makes a nice printbased debugger ; it's easy topoint DTrace at a process and see what's going on (easier than attachinga debugger and getting anywhere in my opinion), and you have a bunch ofinteresting analysis options, none of which require you to

Stated simply: many versions of syslogd will fsync() logfiles afterwriting a messages to them, in an attempt to make sure that the messagemakes it to disk in case something happens to the system immediatelyafterwards (crashes, loses power, etc). This obviously can have animpact (sometimes a significant one) on any other IO activity going onat the time.

On some but not all systems with this feature, you can this off forspecific syslog files by sticking a ' - ' in front of