Re: perf: confused by cc1

From: Xiao Guangrong
Date: Wed Dec 30 2009 - 22:12:58 EST




Dr. David Alan Gilbert wrote:
> Hi,
> I'm running 2.6.33rc2 and thought I'd have a play with perf; its
> symbol resolution code seems to be getting itself a bit confused however:
>
> I recorded a trace of a kernel build like so:
>
> sudo /discs/more/git/linux-2.6/tools/perf/perf record -a -e cycles -i -g -v -s -d make -j 8 bzImage
>
> Then I did:
> /discs/more/git/linux-2.6/tools/perf/perf report -g
>
> and the top entry is:
>
> 69.89% cc1 cc1 [.] 0x000000000337cd
> |
> |--0.99%-- 0x9f5da8
> |
> |--0.74%-- 0x9eec95
> --98.27%-- [...]
>
> but it's refusing to do symbol look up for cc1 even if I install
> the (ubuntu) debug packages (most other files it is doing
> symbol resolution on where they have it). I dug a bit further and
> it looks like it's not trying to look up the debug packages for cc1
> because it think that mapping is a kernel map. Also for some reason it
> thinks the cc1 is an overlapping mapping with the gcc4 binary it's been
> executed from:
>

Your kernel is relocatable? See: http://lkml.org/lkml/2009/12/29/358

Thanks,
Xiao
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