From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <1cb34c5c114ed43b9bc22061a3612578@plan9.bell-labs.com> Subject: Re: [9fans] High interruptload on cpu server From: David Presotto To: 9fans@cse.psu.edu MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Date: Sun, 23 Nov 2003 12:51:08 -0500 Content-Transfer-Encoding: quoted-printable Topicbox-Message-UUID: 91ee8b7e-eacc-11e9-9e20-41e7f4b1d025 If you're on a PC, you can look to see how much time is spent in interrupts by 'acid -k $pid' and dumping the intrtimes array. Take a look at trap.c and you'll understand. It's just an array of 20 buckets for each possible interrupt level. Each bucket represents a 100 =C2=B5 second interval. You'll be able to tell if any one level is hogging a lot of time. I've debated adding a user readable interface but then I'ld have to write a man page. kprof is moderately crappy for timing interrupts since it samples in the clock routine which is splhi'd as are the other interrupt routines, i.e., sampling is mutually exclusive to the interrupt routine running.