Date: Thu, 5 Feb 2015 13:27:50 -0500 From: Brandon Allbery <allbery.b@gmail.com> To: Matthew Grooms <mgrooms@shrew.net> Cc: freebsd-stable <freebsd-stable@freebsd.org> Subject: Re: High load w/ almost no CPU usage Message-ID: <CAKFCL4XQJFPtWOGLTEQQO-7dFmfUkp-Dcde7ky8YM7v_KOHdwg@mail.gmail.com> In-Reply-To: <54D3AC37.8030107@shrew.net> References: <54D3AC37.8030107@shrew.net>
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On Thu, Feb 5, 2015 at 12:45 PM, Matthew Grooms <mgrooms@shrew.net> wrote: > But at seemingly random intervals, the load average jumps to a very high > value, and then eventually drops back down to < 2. One problem with using top to diagnose this kind of thing is that you can have processes that have very short activation periods, which won't show up much in top because they don't run for long enough to collect much CPU time or indeed to produce user-noticeable load, but will drive the apparent load up because they're on the run queue so much. dtrace probes might be more helpful here. Also you might want to look at interrupts (e.g. monitor "vmstat -i" output, then again move to dtrace for finer grained monitoring). -- brandon s allbery kf8nh sine nomine associates allbery.b@gmail.com ballbery@sinenomine.net unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net
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