Re: page_add/remove_rmap costs

[Andrew Morton <akpm@zip.com.au>]

William Lee Irwin III wrote:
> 
> John Levon wrote:
> >> I wrote a patch some time ago to remove all this guesswork on lock call
> >> sites :
> >>
> 
> On Wed, Jul 24, 2002 at 10:47:47PM -0700, Andrew Morton wrote:
> > Me too, but I just killed all the out-of-line gunk, so the cost
> > is shown at the actual callsite.
> 
> It will be applied shortly. I've also been building with -g, so addr2line
> will resolve the rest given appropriate dumping formats.

Hope it still works.

> What's the op_time / oprofpp command that gives per-EIP sample frequencies?

I use

	oprofpp -L -i /boot/vmlinux

oprofile can also allegedly do eip->file-n-line resolution,
but I'm not sure how that works when you're cross-building.
And generally I doubt i it's useful for kernel stuff, because
the EIP usually resolves to something like test_and_set_bit().

So I just fire up gdb on vmlinux and walk up and down a few bytes until
the address->line resolution falls out of the inline function and
into the caller.

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