Re: [PATCH V8 08/25] perf tools: Add Intel BTS support

From: Adrian Hunter
Date: Tue Aug 18 2015 - 05:12:34 EST


On 18/08/15 09:39, Adrian Hunter wrote:
> On 17/08/15 22:58, Arnaldo Carvalho de Melo wrote:
>> Em Mon, Aug 17, 2015 at 10:09:26PM +0300, Adrian Hunter escreveu:
>>> On 17/08/2015 8:58 p.m., Arnaldo Carvalho de Melo wrote:
>>>> Em Mon, Aug 17, 2015 at 08:43:09PM +0300, Adrian Hunter escreveu:
>>>>> On 17/08/2015 6:52 p.m., Arnaldo Carvalho de Melo wrote:
>>>>>> 1.92% usleep [unknown] [.] 0x00007fa0ff695086
>>>>>> 1.60% usleep [unknown] [.] 0xffffffff811c91d0
>>>>>> 1.48% usleep [unknown] [.] 0x00007fa0ffb3030d
>>>>>> 1.24% usleep [unknown] [.] 0x00007fa0ff6950c7
>>>>
>>>>> It is very weird that it doesn't know the dso.
>>>>
>>>>> I presume there is nothing unusual about the environment e.g. in a chroot or anything
>>>>
>>>>> What if you try a different event e.g. perf record --per-thread -e cycles sleep 1
>>>>
>>>> [root@zoo ~]# perf record --per-thread -e cycles sleep 1
>>>> [ perf record: Woken up 1 times to write data ]
>>>> [ perf record: Captured and wrote 0.014 MB perf.data (9 samples) ]
>>>> [root@zoo ~]# perf report | grep -v ^# | head -5
>>>> 42.57% sleep libc-2.20.so [.] malloc_hook_ini
>>>> 41.81% sleep [kernel.vmlinux] [k] filemap_fault
>>>> 14.35% sleep [kernel.vmlinux] [k] flush_tlb_mm_range
>>>> 1.18% sleep [kernel.vmlinux] [k] strlcpy
>>>> 0.09% sleep [kernel.vmlinux] [k] native_write_msr_safe
>>>> [root@zoo ~]#
>>>>
>>>> [root@zoo ~]# perf report --dsos libc-2.20.so | grep -v '^[#]'
>>>> 42.57% sleep [.] malloc_hook_ini
>>>>
>>>> [root@zoo ~]#
>>>>
>>>> [root@zoo ~]# perf record --per-thread -e intel_bts// usleep 1
>>>> [ perf record: Woken up 1 times to write data ]
>>>> [ perf record: Captured and wrote 1.825 MB perf.data ]
>>>> [root@zoo ~]# perf report | grep -v ^# | head -5
>>>> Warning:
>>>> 79074 instruction trace errors
>>>> 2.80% usleep [unknown] [.] 0x00007f48888aa061
>>>> [root@zoo ~]#
>>>
>>> Running out of ideas. Can you somehow share or send me the offending perf.data file?
>>
>> http://vger.kernel.org/~acme/perf/perf.data.intel_bts-4.2.0-rc5+.xz
>
> Says: You don't have permission to access
> /~acme/perf/perf.data.intel_bts-4.2.0-rc5+.xz on this server.
>
>>
>> It works if I use a tip/master kernel:
>>
>> [root@perf4 ~]# uname -r
>> 4.2.0-rc7+
>> [root@perf4 ~]# uname -r
>> 4.2.0-rc7+
>> [root@perf4 ~]# perf record --per-thread -e intel_bts// usleep 1
>> [ perf record: Woken up 1 times to write data ]
>> [ perf record: Captured and wrote 1.785 MB perf.data ]
>> [root@perf4 ~]# dmesg | grep Performance
>> [ 0.188477] Performance Events: PEBS fmt2+, 16-deep LBR, Broadwell
>> events, full-width counters, Intel PMU driver.
>> [root@perf4 ~]# perf report --stdio | grep -v ^# | head -10
>>
>>
>>
>>
>> 10.81% usleep libc-2.17.so [.] _dl_addr
>> 6.56% usleep [kernel.kallsyms] [.] unmap_single_vma
>> 3.33% usleep ld-2.17.so [.] strcmp
>> 2.53% usleep [kernel.kallsyms] [.] mem_cgroup_begin_page_stat
>> 2.49% usleep ld-2.17.so [.] _dl_lookup_symbol_x
>> 2.39% usleep ld-2.17.so [.] _dl_relocate_object
>> [root@perf4 ~]#
>>
>> Probably some fix for the kernel driver is missing?
>
> Works for me though.

I looked at the code and noticed a minor issue, but I don't think it is the
cause of the problem. I sent a fix - see "perf tools: Fix use of wrong
event when processing exit events"

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