Re: Very bad interactivity with 2.6.0 and SCSI disks (aic7xxx)
From: Andrew Morton
Date: Mon Aug 18 2003 - 01:05:38 EST
Stefan Foerster <stefan@xxxxxxxxxxxxxxxxxx> wrote:
>
> * Andrew Morton <akpm@xxxxxxxx> wrote:
> > Stefan Foerster <stefan@xxxxxxxxxxxxxxxxxx> wrote:
> > A kernel profile would be needed to diagnose this. You could use
> > readprofile, but as it may be an interrupt problem, the NMI-based oprofile
> > output would be better.
>
> Is this procedure documented anywhere?
>
Documentation/basic_profiling.txt and oprofile.sourceforge.net.
oprofile is hard to get going and they seem to keep on changing things.
A quick primer would be:
- download the userspace tools, carefully read the INSTALL and README
files.
- You need to do ./configure --with-kernel-support (something like that).
- build and install.
>From my notes, for a P4:
opcontrol --setup --vmlinux=/boot/vmlinux --ctr0-count=600000 --ctr0-unit-mask=1 --ctr0-event=GLOBAL_POWER_EVENTS
For a PIII:
opcontrol --setup --vmlinux=/boot/vmlinux --ctr0-count=600000 --ctr0-event=CPU_CLK_UNHALTED
Then:
opcontrol --shutdown
rm -rf /var/lib/oprofile
opcontrol --start-daemon
opcontrol --start
<run test>
opcontrol --stop
oprofpp -l /boot/vmlinux
oprofpp -Lo /boot/vmlinux > /tmp/1
I use this script.
#!/bin/sh
sudo opcontrol --stop
sudo opcontrol --shutdown
sudo rm -rf /var/lib/oprofile
sudo opcontrol --start-daemon
sudo opcontrol --start
time $@
sudo opcontrol --stop
sudo opcontrol --shutdown
-
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