michallenc opened a new pull request, #16522: URL: https://github.com/apache/nuttx/pull/16522
## Summary `__start` should call `up_perf_init`, initialization of hardware performance counter, if `CONFIG_ARCH_PERF_EVENTS` option is set. This allows the usage of ARM cycle count register `DWT_CYCCNT` in benchmark measurements instead of software clock. ## Impact SAMv7 MCU can now utilize `DWT_CYCCNT` register as hardware performance counter. ## Testing Tested on a custom board with SAMv7 MCU and `osperf` applications. Results without hardware performance counter (normal mode with `CONFIG_USEC_PER_TICK=100`) ``` NuttShell (NSH) NuttX-12.9.0 brcg2> brcg2> osperf OS performance args: count:100, detail:false ============================================================== Describe Max Min Avg pthread-create 100000 0 19000 pthread-switch 0 0 0 pthread-mutex 0 0 0 context-switch 100000 0 4000 hpwork 100000 0 3000 poll-write 100000 100000 24000 pipe 0 0 0 semwait 0 0 0 sempost 0 0 0 ``` Results with the change and `CONFIG_ARCH_PERF_EVENTS` enabled ``` NuttShell (NSH) NuttX-12.9.0 brcg2> brcg2> osperf OS performance args: count:100, detail:false ============================================================== Describe Max Min Avg pthread-create 25063 19220 21120 pthread-switch 4070 2640 3109 pthread-mutex 5086 1923 2118 context-switch 5926 1876 2515 hpwork 13623 3666 4452 poll-write 48900 41163 44407 pipe 7466 5626 6471 semwait 1336 610 699 sempost 833 476 542 ``` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: commits-unsubscr...@nuttx.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
