Lots and lots of system time

Brandon Allbery allbery.b at gmail.com
Fri Nov 25 12:50:21 PST 2011

On Fri, Nov 25, 2011 at 15:08, Harald Hanche-Olsen <hanche at math.ntnu.no>wrote:

> I have no idea what mach_kernel`chud is or does, but it disappears from
> the list when the compilation is stopped. (So do the dtrace functions,
> BTW.) The script runs for ten seconds, so

CHUD is part of the instrumentation, I think (Computer Hardware
Understanding for Developers; if it hasn't been folded into DTrace then it
is at least *used* by DTrace).  You may want to look for "Instruments",
which is part of XCode and makes using DTrace to figure out what a process
is doing much easier.

In any case, I would be interested to see what happens if you turn off
multiple jobs.  I wouldn't necessarily assume that psynch_cvwait doesn't
use CPU, by the way; busywaiting is often used for what are expected to be
short delays waiting on a mutex.  ("port install ... build.njobs=1", IIRC)

brandon s allbery                                      allbery.b at gmail.com
wandering unix systems administrator (available)     (412) 475-9364 vm/sms
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