Re: [LI] kernel profiler

[Arun Sharma <adsharma@xxxxxxxxxxxxxxx>]

On Fri, Dec 17, 1999 at 01:03:23PM +0530, Sharad Joshi wrote:
> + 
> + There is some primitive profiling support in the official kernel.
> + Grep for x86_do_profile. You enable it with a LILO argument and 
> + get the profile data from /proc.
> + 
> 
> That argument is profile=2 or something i suppose, no? Thats how the
> program i have works. It reads from /proc/profile. But i dunno how the
> /proc/profile is arranged. Any info on that?

The command is readprofile. It reads /proc/profile and prints the data
in a readable manner.

If you pass profile=n, x86_do_profile stores (increments the count) 
the current IP at each timer interrupt in one of the 
(kernel code size >> n) buckets. So you get a "rough" i.e. (1 << n) 
approximation of where time is getting spent in the kernel.

When you read /proc/profile, it basically returns the contents of the
buckets.

	-Arun
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