the evil interrupt stats monster is still around!

Matthew Dillon dillon at
Sat Jul 28 16:59:33 PDT 2007

:ktrace.  These are real numbers, not a microbenchmark.  There might be a little bit of load interfering, dunno.  You can grab the dump from <>
:  simon

    Use kdump -R !!! 

    In anycase, it does look odd.  But I can't reproduce the effect
    when I ktrace a similar bmake from pkgsrc and there are cases 
    in your dump where you don't get large timeouts:

66255 sh       1185522939.738309 CALL  fork
66255 sh       1185522939.738419 RET   fork 66264/0x102d8
66255 sh       1185522939.738665 CALL  getpgrp
66255 sh       1185522939.738676 RET   getpgrp 5268/0x1494
66255 sh       1185522939.738730 CALL  wait4(0xffffffff,0xbfbff318,0x2,0)
66264 sh       1185522939.738745 RET   fork 0
				    <----------- 15 uS (326 uS from original
66264 sh       1185522939.739292 CALL  open(0x280de1c8,0x601,0x1b6)
66264 sh       1185522939.739306 NAMI  "/dev/null"
66264 sh       1185522939.739346 RET   open 5

    What it looks like is happening is that there are other processes
    running that get the cpu after the fork/wait4, before the child
    gets the cpu.  Insofar as I can tell it looks like there is a cpu-bound
    program running that is simply not making any system calls to be traced,
    or is not being traced.

    Are you running anything in parallel during this test or running
    a parallel build of some sort?


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