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

[Arnaldo Carvalho de Melo <acme@kernel.org>]

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

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?

- Arnaldo