Re: [PATCH] perf: Add Sparc annotate support.

[David Miller <davem@davemloft.net>]

From: Arnaldo Carvalho de Melo <acme@redhat.com>
Date: Wed, 17 Oct 2018 09:39:02 -0300

> Em Tue, Oct 16, 2018 at 08:55:55PM -0700, David Miller escreveu:
> 
> Great!
> 
> Could you try something like:
> 
> # perf record some_workload
> # perf annotate --stdio2 hot_function
> 
> So that we can see this thing in action, i.e. sparc assembly annotated?
> :-)
> 
> With 'perf annotate --tui hot_function' or 'perf top' 'A' you can
> navigate, but for showing it in action in a git changelog comment
> example --stdio is more convenient :-)

Sure :-)

This is run on __gettimeofday when running perf record on your "gtod"
test.  (Still working on getting glibc to use the VDSO properly on
sparc :-( )

Samples: 7K of event 'cycles:ppp', 4000 Hz, Event count (approx.): 3086733887                                   
__gettimeofday  /lib32/libc-2.27.so [Percent: local period]                                                     
Percent│
       │
       │
       │    Disassembly of section .text:
       │
       │    000a6fa0 <__gettimeofday@@GLIBC_2.0>:
  0.47 │      save   %sp, -96, %sp
  0.73 │      sethi  %hi(0xe9000), %l7
       │    → call   __frame_state_for@@GLIBC_2.0+0x480
  0.30 │      add    %l7, 0x58, %l7     ! e9058 <nftw64@@GLIBC_2.3.3+0x818>
  1.33 │      mov    %i0, %o0
       │      mov    %i1, %o1
  0.43 │      mov    0x74, %g1
       │      ta     0x10
 88.92 │    ↓ bcc    30
  2.95 │      clr    %g1
       │      neg    %o0
       │      mov    1, %g1
  0.31 │30:   cmp    %g1, 0
       │      bne,pn %icc, a6fe4 <__gettimeofday@@GLIBC_2.0+0x44>
       │      mov    %o0, %i0
  1.96 │    ← return %i7 + 8
  2.62 │      nop
       │      sethi  %hi(0), %g1
       │      neg    %o0, %g2
       │      add    %g1, 0x160, %g1
       │      ld     [ %l7 + %g1 ], %g1
       │      st     %g2, [ %g7 + %g1 ]
       │    ← return %i7 + 8
       │      mov    -1, %o0