On October 21, 2022 10:02:05 AM PDT, Alexander Potapenko <glider@xxxxxxxxxx> wrote: >On Fri, Oct 21, 2022 at 8:19 AM youling 257 <youling257@xxxxxxxxx> wrote: > >> 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. >> >Will it help if you disable CONFIG_RANDOMIZE_BASE? >(if it doesn't show the symbols, at least we'll be able to figure out the >offending function by running nm) Is KALLSYMS needed? > > >> >> 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@xxxxxxxxxx>: >> > On Thu, 20 Oct 2022 at 23:39, youling 257 <youling257@xxxxxxxxx> 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@xxxxxxxxxx>: >> >> > On Thu, 20 Oct 2022 at 22:55, youling 257 <youling257@xxxxxxxxx> >> 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. >> >> > >> > >> > > -- Kees Cook
