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SubjectRe: [PATCH -tip v4 0/5] perf script: add BTS analysis features
On Mon, Jan 16, 2012 at 02:21:46PM +0900, Akihiro Nagai wrote:
> Hi Frederic, David,
> This patch series adds the functions to analyze BTS logs to perf-script and,
> makes perf-script more informative version 4.
> The patches add the following functions.
> - Unify the expression to "[unknown]"
> - Fix BTS record header to resolve DSOs and symbols of user-space
> - Resolve DSOs and symbols for BTS's branch_from addresses
> - Show the offset of symbols with the 'offs' field specifier.
> - Resolve the real path of [kernel.kallsym] using
> '--show-kernel-path' option.
> Usage:
> First, get the BTS log with the following command.
> # perf record -e branches:u -c 1 -d <command>
> Second, analyze that trace data.
> # perf script -f ip,addr,sym,offs,dso [--show-kernel-path]
> This command's output format is:
> <branch_to addr> <branch_to function+offset> <branch_to DSO> <branch_from addr> <branch_from function+offset> <branch_from DSO>
> Output sample:
> # perf record -e branches:u -c 1 -d ls
> [snip]
> # perf script -f ip,addr,sym,dso,offs --show-kernel-path
> [snip]
> 402c1c main+0x0 (/root/bin/ls) 3430c21399 __libc_start_main+0xe9 (/lib64/

I was confused first, looking for the reason why we have a so strange branch flow
until I realized the format is "to from".

Can we have "from to" instead? This will be much more intuitive. "from => to" would be even better.


> 40b390 set_program_name+0x0 (/root/bin/ls) 402c41 main+0x25 (/root/bin/ls)
> 40b390 set_program_name+0x0 (/root/bin/ls) ffffffff814ac5ed irq_return+0x0 (/lib/modules/3.2.0+/build/vmlinux)
> 401e20 strrchr@plt+0x0 (/root/bin/ls) 40b39e set_program_name+0xe (/root/bin/ls)
> 401e26 strrchr@plt+0x6 (/root/bin/ls) 401e20 strrchr@plt+0x0 (/root/bin/ls)
> 401b80 _init+0x18 (/root/bin/ls) 401e2b strrchr@plt+0xb (/root/bin/ls)
> 3430813850 _dl_runtime_resolve+0x0 (/lib64/ 401b86 _init+0x1e (/root/bin/ls)
> [snip]

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