On 09/10/13 13:12, Jiri Olsa wrote:
> On Wed, Oct 09, 2013 at 10:33:25AM +0300, Adrian Hunter wrote:
>> On 08/10/13 17:02, Jiri Olsa wrote:
>>> On Tue, Oct 08, 2013 at 11:45:50AM +0300, Adrian Hunter wrote:
>>>> objdump fails to annotate module symbols when looking
>>>> at kcore. Workaround this by extracting object code
>>>> from kcore and putting it in a temporary file for
>>>> objdump to use instead. The temporary file is created
>>>> to look like kcore but contains only the function
>>>> being disassembled.
>>>
>>> Excited to ses this one, but looks like I'm hitting some
>>> issue. All annotation starts for me like this:
>>>
>>>
>>> ▒
>>> │ Disassembly of section load0:
>>> ▒
>>> │
>>> ▒
>>> │ ffffffff815eee80 <load0>:
>>> ◆
>>> 9.33 │ffffffff815eee80: data32 data32 data32 xchg %ax,%ax
>>>
>>>
>>>
>>> which does not seem right
>>
>> Can you tell me the commits of the kernel and perf tools you
>> were using, plus the commands and what symbol it was?
>
> kernel: 3.9.10-100.fc17.x86_64
> perf: latest acme's perf/core (06de626 perf evlist: Fix
> perf_evlist__mmap_read event overflow )
> plus your V5 patches
>
> commands:
> sudo ./perf record -e cycles:k -a
> sudo ./perf report
>
> ---
> Samples: 2K of event 'cycles:k', Event count (approx.): 445188286
>
> 14.73% swapper [kernel.kallsyms] [k] intel_idle
> ◆
> 3.19% X [kernel.kallsyms] [k] smp_call_function_many
> ▒
> 1.58% X [kernel.kallsyms] [k] i915_gem_write_fence__ipi
> ▒
> 1.58% swapper [kernel.kallsyms] [k] iwl_trans_pcie_read32
> ▒
>
>
> annotation of 1st 4 symbols:
>
> ---
> intel_idle /proc/kcore
>
> │
> ▒
> │
> ▒
> │
> ▒
> │ Disassembly of section load0:
> ▒
> │
> ▒
> │ ffffffff8135f490 <load0>:
> ▒
> 1.18 │ data32 data32 data32 xchg %ax,%ax
> ▒
>
>
> ---
> smp_call_function_many /proc/kcore
>
> │
> ◆
> │
> ▒
> │
> ▒
> │ Disassembly of section load0:
> ▒
> │
> ▒
> │ ffffffff810bc270 <load0>:
> ▒
> │ data32 data32 data32 xchg %ax,%ax
> ▒
>
> ---
> i915_gem_write_fence__ipi /proc/kcore
>
> │
> │
> │
> │ Disassembly of section load0:
> │
> │ ffffffffa0086630 <load0>:
> │ data32 data32 data32 xchg %ax,%ax
>
> ---
> iwl_trans_pcie_read32 /proc/kcore
>
> │
> │
> │
> │ Disassembly of section load0:
> │
> │ ffffffffa0414a50 <load0>:
> │ data32 data32 data32 xchg %ax,%ax
>
>
> the rest of the instruction decode differs.. just the first
> line is same for all
>
> addresses seem ok:
>
> [jolsa@krava perf]$ egrep
> 'ffffffff8135f490|ffffffff810bc270|ffffffffa0086630|ffffffffa0414a50'
> /proc/kallsyms
> ffffffff810bc270 T smp_call_function_many
> ffffffff8135f490 t intel_idle
> ffffffffa0414a50 t iwl_trans_pcie_read32 [iwlwifi]
> ffffffffa0086630 t i915_gem_write_fence__ipi [i915]
>
> so.. the name of the section, name of the <function> plus the first
> instruction decode seem wrong.. I can see that in every symbol I
> annotate in the report and in annotate command as well.
If you use the --asm-raw option you can see the bytes:
66 66 66 90
That looks like a "nop" e.g. K8_NOP4 in arch/x86/include/asm/nops.h
/*
* Define nops for use with alternative() and for tracing.
*
* *_NOP5_ATOMIC must be a single instruction.
*/
#define NOP_DS_PREFIX 0x3e
/* generic versions from gas
1: nop
the following instructions are NOT nops in 64-bit mode,
for 64-bit mode use K8 or P6 nops instead
2: movl %esi,%esi
3: leal 0x00(%esi),%esi
4: leal 0x00(,%esi,1),%esi
6: leal 0x00000000(%esi),%esi
7: leal 0x00000000(,%esi,1),%esi
*/
#define GENERIC_NOP1 0x90
#define GENERIC_NOP2 0x89,0xf6
#define GENERIC_NOP3 0x8d,0x76,0x00
#define GENERIC_NOP4 0x8d,0x74,0x26,0x00
#define GENERIC_NOP5 GENERIC_NOP1,GENERIC_NOP4
#define GENERIC_NOP6 0x8d,0xb6,0x00,0x00,0x00,0x00
#define GENERIC_NOP7 0x8d,0xb4,0x26,0x00,0x00,0x00,0x00
#define GENERIC_NOP8 GENERIC_NOP1,GENERIC_NOP7
#define GENERIC_NOP5_ATOMIC NOP_DS_PREFIX,GENERIC_NOP4
/* Opteron 64bit nops
1: nop
2: osp nop
3: osp osp nop
4: osp osp osp nop
*/
#define K8_NOP1 GENERIC_NOP1
#define K8_NOP2 0x66,K8_NOP1
#define K8_NOP3 0x66,K8_NOP2
#define K8_NOP4 0x66,K8_NOP3
#define K8_NOP5 K8_NOP3,K8_NOP2
#define K8_NOP6 K8_NOP3,K8_NOP3
#define K8_NOP7 K8_NOP4,K8_NOP3
#define K8_NOP8 K8_NOP4,K8_NOP4
#define K8_NOP5_ATOMIC 0x66,K8_NOP4
I think what you see is correct.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
