利用亚微秒精度测量Linux内核空间的时间

Question

I am currently using the do_gettimeofday() function to measure time in the kernel, which gives me microsecond precision. Is there anything available that is more precise than this (maybe on the order of nanoseconds)?

Answer 1

ktime_get()函数返回ktime_t ，其具有纳秒分辨率。

Answer 2

As I know, the most precise timer should be the processor specific counter register (such as TSC in x86). Linux kernel provide rdtsc, rdtscl, rdtscll macros from the "./arch/x86/include/asm/msr.h" file to read this register value. For ARM, cycle counter register .

These registers are all different from CPU to CPU. Common interface to access it is "get_cycles" function which is declared in file.

Maybe, this document can be helpful.