I have revised the patch based on the comments below:

	1) use ip instead of eip
	2) multiply ri by 4, to get more compact histograms

  -Will

David Mosberger wrote:
>>>>>>On Tue, 26 Aug 2003 16:42:27 -0400, Will Cohen <wcohen@redhat.com> said:
>>>>>
> 
>   Will> +	eip = instruction_pointer(regs);
> 
> eip?  How about calling it "ip", which is the register name and what's
> used everywhere else in the ia64 tree.
> 
>   Will> +/*
>   Will> + * We use the ia64_psr(regs)->ri to determine which of the three
>   Will> + * instructions in bundle took the sample. The instructions in the
>   Will> + * ia64 do not fall on nice four byte boundaries, so there is no point
>   Will> + * in multiplying ia64_psr(regs)->ri by 4.
>   Will> + */
>   Will> +#define instruction_pointer(regs) ((regs)->cr_iip + ia64_psr(regs)->ri)
> 
> How are you going to get instruction-level precision with this?
> 
> Given this:
> 
>   Will> -	ip >>= prof_shift;
> 
> you'd have to use a prof_shift of 0, which is wasteful.  If you
> multiply ri by 4, you can use a prof_shift of 2, reducing the
> histogram size by a factor of 4 while still getting instruction-level
> accuracy.
> 
> I can see why you don't want to do the multiply-by-four in
> instruction_pointer(), but if that's what you want to avoid, I think
> ia64_do_profile() should should do it so we can get the desired
> effect.
> 
> 	--david