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. > >
