Re: [PATCH 2/3] perf tools: Add callchain order support for libunwind DWARF unwinder
From: Jiri Olsa
Date: Wed Nov 18 2015 - 02:54:39 EST
On Wed, Nov 18, 2015 at 12:13:08PM +0800, Wangnan (F) wrote:
> 3.38% a.out a.out [.] funcc
> |--2.70%-- funcb
> | funca
> | main
> | __libc_start_main
> | _start
> --0.68%-- 0
> I'm not sure whether we can regard this behavior changing as a bugfix? I
> there may be some reason the original code explicitly avoid creating an '0'
> Then I tried to find why perf can't get call frame on my case, and
> I guess there's something wrong whe dealing with 'call' command, because
> the instruction on it I can't get callchain from libunwind is a 'callq':
> 4005bf: be 00 00 00 00 mov $0x0,%esi
> 4005c4: 48 89 c7 mov %rax,%rdi
> 4005c7: e8 74 fe ff ff callq 400440 <gettimeofday@plt>
> us2 = tv2.tv_sec * 1000000 + tv2.tv_usec;
> 4005cc: 48 8b 04 24 mov (%rsp),%rax
> But this is another problem, we can discuss it in a new thread.
so the problem is you dont see the gettimeofday call at the end?
could you share the test code?
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