I/O waits
Date: 14 Feb 2003 09:15:30 -0800

prex on Solaris

Follow the instruction in Adrian Cockcroft's Sun Performance Tuning
(or Programming Utilities Guide from docs.sun.com) and make sure you
use pfilter to focus on that shadow process only. Roughly it goes like
this:

# prex -k
  buffer alloc 100m
  enable io
  pfilter add <processid>
  trace io
  ktrace on

After tnfxtract and tnfdump, the result looks like this:

   121857.390444      1736.011796  3736     1 0x300       18 pagein
vnode: 0x3000d20ab38 offset: 0 size: 8192

   121857.400640         0.010196  3736     1 0x300       18 strategy
device: 6 block: 2610480 size: 8192 buf: 0x30000758630 flags: 524377
...

The first two numbers are elapsed time and delta time. You need to
find the file from the vnode. I think crash has a function for it...
Quite a bit of work.

Remember to disable tracing and deallocate the kernel buffer after
you're done.

Yong Huang