Hi
On 19 May 2014 16:08, Prankul Garg <prankul.ii...@gmail.com> wrote:
> Jean Pihet <jean.pihet@...> writes:
>
>>
>> Hello,
>>
>> Indeed there is a problem in the ARM code for tracepoints.
>> After a good discussion with the perf maintainers a solution has be
>> found, cf. http://www.spinics.net/lists/arm-kernel/msg332293.html.
>>
>> Can you check if this fixes the problem? It does on my side on 3.15-rc4.
>
> Hi Jean,
>
> yes, it solved the problem but partially, i am getting different outputs for
> x86 and ARM.
>
> On x86(3.10.28):
>
> ./perf record -e kmem:kmalloc cal
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.009 MB perf.data (~381 samples) ]
>
> ./perf report
> # Overhead Command Shared Object Symbol
> # ........ ....... ................. ..........................
> #
> 96.77% cal [kernel.kallsyms] [k] kmem_cache_alloc_trace
> 3.23% cal [kernel.kallsyms] [k] __kmalloc
>
> ./perf report -v
> 96.77% cal /lib/modules/3.10.28+/build/vmlinux 0xffffffff81166f6d
> v [k] kmem_cache_alloc_trace
> 3.23% cal /lib/modules/3.10.28+/build/vmlinux 0xffffffff81166b24
> v [k] __kmalloc
>
> ./perf buildid-list
> aef9a24fcddff67cd67bcc1fd27dbeaf86d35487 [kernel.kallsyms]
>
>
> but on ARM(3.4.0):
>
> ./perf record -e kmem:kmalloc cal
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.004 MB perf.data (~192 samples) ]
>
> ./perf report
> # Overhead Command Shared Object Symbol
> # ........ ....... ................. ..........................
> #
> 100.00% cal [ks8851] [k] 0x01247890
>
> ./perf report -v
> 100.00% cal /lib/modules/3.4.0/.../ks8851.ko 0x1247890 l [k]
> 0x01247890
>
> ./perf buildid-list
> d0898c01486575dddafc6686240186bdb4b4430a /lib/modules/3.4.0/.../ks8851.ko
>
>
> that means on ARM, it is not getting the buildid for [kernel.kallsyms].
>
> Are you getting the same output for ARM and x86 ??
Yes. Here is the output I have:
root@axp-linaro:/home/linaro/linaro/kernel# ./linux/tools/perf/perf report -v
build id event received for vmlinux: 6db809b8adab308f64037970799dc836f6b96422
Looking at the vmlinux_path (6 entries long)
Using /proc/kallsyms for symbols
# To display the perf.data header info, please use --header/--header-only option
#
# Samples: 12 of event 'kmem:kmalloc'
# Event count (approx.): 12
#
# Overhead Command Shared Object Sy
# ........ ............ ................. ...................................
#
91.67% stress_bt_v7 [kernel.kallsyms] 0xc00f1548 k [k] kmem_cache_alloc_t
8.33% stress_bt_v7 [kernel.kallsyms] 0xc00f1400 k [k] __kmalloc
#
# (For a higher level overview, try: perf report --sort comm,dso)
#
root@axp-linaro:/home/linaro/linaro/kernel/linux# ./tools/perf/perf
buildid-list
6db809b8adab308f64037970799dc836f6b96422 vmlinux
root@axp-linaro:/home/linaro/linaro/kernel/linux#
perf is looking for symbols in vmlinux (if present in the current dir
or specified in the command line) and if not found from kallsyms. So
if I run 'perf report' from the kernel root dir, the symbols are from
vmlinux; if I run it from elsewhere the symbols are from kallsyms.
Also your build is quite old, a lot of changes went into perf since 3.4.
Regards,
Jean
>
> regards,
> Prankul Garg
>
>>
>> The patch is under review by the ARM experts and hopefully should be
>> merged soon.
>>
>> Regards,
>> Jean
>>
>> On 16 May 2014 09:34, Jean Pihet <jean.pihet@...> wrote:
>> > Hello,
>> >
>> >
>> > On 15 May 2014 07:36, sneha priya <sneha.cse@...> wrote:
>> >> Hello,
>> >>
>> >> There is an issue related to perf which I am facing since 15 days.
> Hoping
>> >> that the great minds here will help me to solve this.
>> >>
>> >> I have a requirement to make perf tool work on a device having ARM
>> >> architecture. But, on recording the tracepoint events and then running
>> >> ./perf report, it shows the shared objects name as [unknown] and
> Symbols as
>> >> 00000, whereas for software and hardware events I do not experience
> this
>> >> issue.
>> >> I have cross compiled the perf tool available on mailine and ported it
> on a
>> >> device having ARM architecture.
>> >>
>> >> Output on ARM based device with kernel 3.4.
>> >>
>> >> ./perf record -e kmem:kmalloc cal
>> >>
>> >> [ perf record: Woken up 1 times to write data ]
>> >> [ perf record: Captured and wrote 0.007 MB perf.data (~321 samples) ]
>> >>
>> >> ./perf report
>> >>
>> >> Overhead Command Shared Object
>> >> Symbol
>> >> ........................... ................................
>> >> ...........................................
>> >> 40.78% cal [unknown]
>> >> [.]00000000
>> >> 31.6% cal [unknown]
>> >> [.]00000000
>> >>
>> >> [...]
>> >>
>> >> On ubuntu 12.04, system (kernel 3.10) it works perfectly fine.
>> >>
>> >> Output on x86 architecture
>> >>
>> >> ./perf record -e kmem:kmalloc gcalctool
>> >>
>> >> [ perf record: Woken up 3 times to write data ]
>> >> [ perf record: Captured and wrote 0.27 MB perf.data (~845 samples) ]
>> >>
>> >> ./perf report --stdio
>> >>
>> >> Overhead Command
> Shared
>> >> Object Symbol
>> >> ........................... ................................
>> >> ...........................................
>> >> 96.55% cal
>> >> [kernel.kallsyms] [k] kmem_cache_alloc_trace
>> >> 3.45% cal
>> >> [kernel.kallsyms] [.]__kmalloc
>> >>
>> >> [...]
>> >>
>> >>
>> >> Keenly, awaiting for you help.
>> >
>> > There are a few things to check. Note that the 3.4 kernel is OK wrt
>> > perf and tracepoints but is quite old, the recent development now
>> > happens on 3.15.
>> >
>> > - Do you have kallsyms enabled in your kernel (CONFIG_KALLSYMS=y)?
>> > - Are there warnings issued by perf record, e.g. access to kernel
> symbols etc?
>> > - perf report needs to know about your vmlinux image (the one that
>> > contains the debug symbols etc in the root directory of the kernel
>> > build). You can use '-k <file>' or '--vmlinux=<file>', cf. perf report
>> > --help.
>> > - You can dump the samples from perf.data using perf report -D. The
>> > entries with 'PERF_RECORD_SAMPLE(IP, 2)' are for the user space apps.
>> > - The '-v' option gives more info. This can be used multiple times ('-
> vv').
>> >
>> >>
>> >> Thanks.
>> >>
>> >> Sneha.
>> >
>> > Regards,
>> > Jean
>> >
>> >>
>> >> _______________________________________________
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>> >> linaro-dev@...
>> >> http://lists.linaro.org/mailman/listinfo/linaro-dev
>> >>
>>
>
>
>
>
>
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