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SubjectRe: [PATCH -tip ] [BUGFIX] perf probe: Fix to probe on symbols with optimization suffix
Hi Arnaldo,

BTW, I also found another issue which the perf probe -l showed
incorrect line number and file name for probes on such inline
functions. :(
I found the root causes (the line info is not correct and
perf probe failed to handle nested inline functions). I'll send
the bugfix patch soon.

Thank you,

(2013/09/26 0:38), Arnaldo Carvalho de Melo wrote:
> Em Wed, Sep 25, 2013 at 10:16:16PM +0900, Masami Hiramatsu escreveu:
>> Fix perf probe to probe on some symbols which have some
>> optimzation suffixes, e.g. ".part", ".isra", and ".constprop".
>> To fix this issue, instead of using DIE name, perf probe
>> uses symbol name found by dwfl_module_addrsym().
>
> Thanks Masami! Now it behaves _exactly_ as I expected and need:
>
> [root@zoo linux]# perf probe -L getname_flags:65
> <getname_flags@/home/git/linux/fs/namei.c:65>
> 65 result->uptr = filename;
> 66 audit_getname(result);
> return result;
>
> error:
> 70 final_putname(result);
> 71 return err;
> 72 }
>
> struct filename *
> getname(const char __user * filename)
>
> [root@zoo linux]# perf probe -V getname_flags:65
> Available variables at getname_flags:65
> @<getname_flags.part.35+178>
> char* filename
> int* empty
> long int max
> struct filename* result
> [root@zoo linux]# perf probe 'getname_flags:66 pathname=result->name:string'
> Added new event:
> probe:getname_flags (on getname_flags:66 with pathname=result->name:string)
>
> You can now use it in all perf tools, such as:
>
> perf record -e probe:getname_flags -aR sleep 1
>
> [root@zoo linux]# perf record -a -e probe:getname_flags
> ^C[ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 1.252 MB perf.data (~54692 samples) ]
> [root@zoo linux]# perf script | grep -v '# | head -5
>> ^C
> [root@zoo linux]# perf script | grep -v '^#' | head -5
> libvirtd 1163 [001] 100606.469450: probe:getname_flags: (ffffffff811a2f89) pathname="/proc/cpuinfo"
> libvirtd 1163 [001] 100606.469563: probe:getname_flags: (ffffffff811a2f89) pathname="/sys/devices/system/node"
> libvirtd 1163 [001] 100606.469596: probe:getname_flags: (ffffffff811a2f89) pathname="/sys/devices/system/node/node0"
> libvirtd 1163 [001] 100606.469612: probe:getname_flags: (ffffffff811a2f89) pathname="/sys/devices/system/node/node0/cpu0/online"
> libvirtd 1163 [001] 100606.469628: probe:getname_flags: (ffffffff811a2f89) pathname="/sys/devices/system/node/node0/cpu0/topology/physical_package_id"
> [root@zoo linux]#
>
> Thanks a lot, applied to my perf/urgent branch,
>
> - Arnaldo
>


--
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com




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