[linuxkernelnewbies] Oprofile setup - OLPC

Sun, 12 Oct 2008 07:39:14 -0700

http://wiki.laptop.org/go/Oprofile_setup

Oprofile setup

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[edit] Setting Up OProfile to Run on OLPC Laptop

It is possible to get OProfile in timer mode working on the olpc machine. Performance monitoring hardware on Geode process is not supported. The jffs2 file system does NOT support the mechanism that OProfile uses. You will need another file system such as ramfs filesystem or USB flash drive formatted as ext3 or VFAT to store the OProfile data.

[edit] OLPC Machine Steps

  • 1) Install binutils and oprofile: 
yum install binutils oprofile

Or 

init 3; 
yum -yt install binutils oprofile
  • 2) If running from an image in the internal jffs2 file system, you will need to mount another file system to store the samples. Below are examples of the commands to set that up. You will need to modify for local conditions. 
mkdir /var/lib/oprofile
mount -t ramfs none /var/lib/oprofile

Or 

mkdir /media/usbflash
mount -t ext3 /dev/sda1 /media/usbflash
rm -rf /var/lib/oprofile/samples/current
mkdir /media/usbflash/samples
ln -s /media/usbflash/samples /var/lib/oprofile/samples/current
  • 3) As root configure OProfile to collect data: 
opcontrol --setup --vmlinux=/root/vmlinux --separate=library

If you do not care about kernel data, you can skip installing vmlinux and configure with: 

opcontrol --setup --no-vmlinux --separate=library
  • 4) As root start oprofile running with: 
opcontrol --start
  • 5) Do desired experiment to collect data
  • 6) As root shutdown OProfile with: 
opcontrol --shutdown
  • 7) Look at the data with the "opreport" command.
  • 8) Unmount filesystem storing OProfile samples if needed.

[edit] Discussions about Oprofile @ devel

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