Re: [PATCH 1/2] perf tools powerpc: Fix callchain ip filtering

[Sandipan Das]

On 04/17/2018 12:29 PM, Ravi Bangoria wrote:
> 
> This change looks good to me but seems it fixed the issue
> partially.Ex,
> 
> ÂÂÂ # readelf --debug-dump=frames-interp /lib64/libc-2.26.so | less
> ÂÂÂ ...
> ÂÂÂ 00005778 0000000000000024 0000577c FDE cie=00000000 pc=0000000000048b30..0000000000048c64
> ÂÂÂÂÂÂ LOCÂÂÂÂÂÂÂÂÂÂ CFAÂÂÂÂÂ r31ÂÂ raÂÂÂ
> ÂÂÂ 0000000000048b30 r1+0ÂÂÂÂ uÂÂÂÂ uÂÂÂÂ
> ÂÂÂ 0000000000048b40 r1+0ÂÂÂÂ c-8ÂÂ r0ÂÂÂ
> ÂÂÂ 0000000000048b58 r1+64ÂÂÂ c-8ÂÂ c+16Â
> ÂÂÂ 0000000000048bd8 r1+0ÂÂÂÂ c-8ÂÂ c+16Â
> ÂÂÂ 0000000000048be4 r1+0ÂÂÂÂ uÂÂÂÂ
> ÂÂÂ 0000000000048bf0 r1+64ÂÂÂ c-8ÂÂ c+16Â
> 
> 0000000000048b30..0000000000048c64 is arandom() function from libc:
> 
> ÂÂÂ 0000000000048b30 <random>:
> ÂÂÂÂÂÂ 48b30:ÂÂÂÂÂÂ 1c 00 4c 3cÂÂÂÂ addisÂÂ r2,r12,28
> ÂÂÂÂÂÂ 48b34:ÂÂÂÂÂÂ d0 e5 42 38ÂÂÂÂ addiÂÂÂ r2,r2,-6704
> ÂÂÂÂÂÂ 48b38:ÂÂÂÂÂÂ a6 02 08 7cÂÂÂÂ mflrÂÂÂ r0
> ÂÂÂÂÂÂ 48b3c:ÂÂÂÂÂÂ f8 ff e1 fbÂÂÂÂ stdÂÂÂÂ r31,-8(r1)
> ÂÂÂÂÂÂ 48b40:ÂÂÂÂÂÂ 00 00 00 60ÂÂÂÂ nop
> ÂÂÂÂÂÂ 48b44:ÂÂÂÂÂÂ 00 00 20 39ÂÂÂÂ liÂÂÂÂÂ r9,0
> ÂÂÂÂÂÂ 48b48:ÂÂÂÂÂÂ 80 b5 e2 3bÂÂÂÂ addiÂÂÂ r31,r2,-19072
> ÂÂÂÂÂÂ 48b4c:ÂÂÂÂÂÂ 01 00 00 39ÂÂÂÂ liÂÂÂÂÂ r8,1
> ÂÂÂÂÂÂ 48b50:ÂÂÂÂÂÂ 10 00 01 f8ÂÂÂÂ stdÂÂÂÂ r0,16(r1)
> ÂÂÂÂÂÂ 48b54:ÂÂÂÂÂÂ c1 ff 21 f8ÂÂÂÂ stduÂÂÂ r1,-64(r1)
> ÂÂÂÂÂÂ 48b58:ÂÂÂÂÂÂ f0 8f 4d e9ÂÂÂÂ ldÂÂÂÂÂ r10,-28688(r13)
> Â Â ÂÂ ...
> 
> Your change fixed the issue for 48b30..48b40. But not for
> 48b40..48b58.
> 
> I probed at 0x48b40.
> 
> ÂÂÂ # ./perf record -g -e probe_libc:abs_48b40 ~/rand
> 
> perf report without Suka's and your change:
> 
>  # Children Self Trace outputÂ
>  # ........ ........ ..............
> ÂÂÂ #
> ÂÂÂÂÂÂ 100.00%ÂÂ 100.00%Â (7fffb7d28b40)
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ ---0
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ __libc_start_main
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ generic_start_main.isra.0
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ main
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ rand
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ __random
> 
> perf report with only Suka's change:
> 
>  # Children Self Trace outputÂ
>  # ........ ........ ..............
> ÂÂÂ #
> ÂÂÂÂÂÂ 100.00%ÂÂ 100.00%Â (7fffb7d28b40)
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ ---0
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ __libc_start_main
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ generic_start_main.isra.0
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ main
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ __random
> 
> perf report with Suka's and your change:
> 
>  # Children Self Trace outputÂ
>  # ........ ........ ..............
> ÂÂÂ #
> ÂÂÂÂÂÂ 100.00%ÂÂ 100.00%Â (7fffb7d28b40)
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ ---0
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ __libc_start_main
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ generic_start_main.isra.0
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ main
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ __random
> 
> I think rand() is a valid entry which is missing in last two cases.
> 
> 

Ah, good catch and thanks for the review. Will address these problems in v2.

- Sandipan