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Date: Wed, 09 Oct 2013 13:38:04 +0300 From: Adrian Hunter <adrian.hunter@...el.com> To: Jiri Olsa <jolsa@...hat.com> CC: Arnaldo Carvalho de Melo <acme@...stprotocols.net>, Peter Zijlstra <a.p.zijlstra@...llo.nl>, linux-kernel@...r.kernel.org, David Ahern <dsahern@...il.com>, Frederic Weisbecker <fweisbec@...il.com>, Mike Galbraith <efault@....de>, Namhyung Kim <namhyung@...il.com>, Paul Mackerras <paulus@...ba.org>, Stephane Eranian <eranian@...gle.com> Subject: Re: [PATCH V5 3/9] perf tools: workaround objdump difficulties with kcore 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@...va 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 majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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