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From: Johan Tibell <johan.tibell@gmail.com>
To: linux-perf-users@vger.kernel.org
Subject: 'annotate' confusingly reports 'add' instruction as taking most CPU time
Date: Mon, 30 Sep 2013 21:06:56 -0700	[thread overview]
Message-ID: <CAK-tuPbbbWcbJxk88xO_urj2ktk861xnG+tkOs0cZBjnowjMeA@mail.gmail.com> (raw)

Hi,

I'm trying to use 'perf record' to find the hotspot inside a function.
The results I'm seeing are confusing. 'annotate' claims that a simple
'add' instruction is the main CPU time consumer"

        0.00 :          408246:       mov    0x8(%rbp),%rsi
                                                               0.31 :
        40824a:       mov    0x10(%rbp),%rcx
                                              0.00 :          40824e:
     lea    0x4(%rcx),%rdi
                                0.81 :          408252:       mov
0x6(%rbx),%rbx
                  0.00 :          408256:       mov
0x18(%rbx,%rax,8),%r8
     --->   27.58 :          40825b:       add    $0x20,%rbp

0.00 :          40825f:       jmpq   408338 <Main_zdwpolyzugo_info>
                                             0.00 :          408264:
    mov    $0x7b9609,%ebx
                           0.00 :          408269:       add
$0x20,%rbp
                    0.00 :          40826d:       jmpq   *0x0(%rbp)

        5.41 :          408270:       mov    0xd(%rbx),%rax

How shall I interpret this? Is it really the following jump that is to blame?

-- Johan

             reply	other threads:[~2013-10-01  4:07 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-01  4:06 Johan Tibell [this message]
2013-10-01 12:53 ` 'annotate' confusingly reports 'add' instruction as taking most CPU time Vince Weaver
2013-10-01 15:14   ` Johan Tibell

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