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

[Arnaldo Carvalho de Melo]

Em Tue, Aug 18, 2015 at 09:39:46AM +0300, Adrian Hunter escreveu:
> 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.

Ooops, fixed.
 
> > 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.

Works for you if you test in lockstep the tooling with the kernel
sources, right? It works for me as well, if I use the latest tip/master
tooling _and_ kernel, my report was for using the 4.2.0-rc latest for
the kernel and the tooling in tip/master.

I think this would be just a matter of having a better message, or
perhaps some fix that we need to send to the stable@xxxxxxxxxx guys, so
that the new tooling works with a slightly older kernel.

Anyway, consider looking at that perf.data file that I fixed the
permissions on vger, and I will look at the fix you mentioned in another
message.

- Arnaldo
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