aarch64 cycle count with frequency (#179)

Signed-off-by: Coldwings <coldwings@me.com>
alibaba · Aug 22, 2023 · c5fb639 · c5fb639
1 parent 72c37b6
commit c5fb639
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/thread/thread.cpp b/thread/thread.cpp
@@ -973,8 +973,11 @@ R"(
  return (hi << 12) | (low >> 20);
  #elif defined(__aarch64__)
  uint64_t val;
+ uint64_t freq;
  asm volatile("mrs %0, cntvct_el0" : "=r" (val));
- return (uint32_t)(val >> 20);
+ asm volatile("mrs %0, cntfrq_el0" : "=r" (freq));
+ // cycles * microsec_per_sec / frequency = microsec
+ return (val << 10) / freq;
  #endif
  }
  static uint32_t last_tsc = 0;