Re: [PATCH v7 18/43] instrumented.h: add KMSAN support

youling 257
2022-10-21T15:19:43Z

CONFIG_DEBUG_INFO=y
CONFIG_AS_HAS_NON_CONST_LEB128=y
# CONFIG_DEBUG_INFO_NONE is not set
CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y
# CONFIG_DEBUG_INFO_DWARF4 is not set
# CONFIG_DEBUG_INFO_DWARF5 is not set
# CONFIG_DEBUG_INFO_REDUCED is not set
# CONFIG_DEBUG_INFO_COMPRESSED is not set
# CONFIG_DEBUG_INFO_SPLIT is not set
# CONFIG_DEBUG_INFO_BTF is not set
# CONFIG_GDB_SCRIPTS is not set

perf top still no function name.

12.90% [kernel] [k] 0xffffffff833dfa64
3.78% [kernel] [k] 0xffffffff8285b439
3.61% [kernel] [k] 0xffffffff83370254
2.32% [kernel] [k] 0xffffffff8337025b
1.88% bluetooth.default.so [.] 0x000000000000d09d

2022-10-21 15:37 GMT+08:00, Marco Elver <elver@google.com>:
> On Thu, 20 Oct 2022 at 23:39, youling 257 <youling257@gmail.com> wrote:
>>
>> PerfTop: 8253 irqs/sec kernel:75.3% exact: 100.0% lost: 0/0 drop:
>> 0/17899 [4000Hz cycles], (all, 8 CPUs)
>> ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>>
>> 14.87% [kernel] [k] 0xffffffff941d1f37
>> 6.71% [kernel] [k] 0xffffffff942016cf
>>
>> what is 0xffffffff941d1f37?
>
> You need to build with debug symbols:
> CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y
>
> Then it'll show function names.
>
>> 2022-10-21 14:16 GMT+08:00, Marco Elver <elver@google.com>:
>> > On Thu, 20 Oct 2022 at 22:55, youling 257 <youling257@gmail.com> wrote:
>> >>
>> >> How to use perf tool?
>> >
>> > The simplest would be to try just "perf top" - and see which kernel
>> > functions consume most CPU cycles. I would suggest you compare both
>> > kernels, and see if you can spot a function which uses more cycles% in
>> > the problematic kernel.
>> >
>