3 ms·
> Because of the overheads, I wouldn't trust the high resolution timestamps also included in the blog post. Naive question why would the timestamps be inaccura
by gbrown_ 10y ago
> Because of the overheads, I wouldn't trust the high resolution timestamps also included in the blog post.
Naive question why would the timestamps be inaccurate, surely each step of the program's execution should just be slower? Am I missing something about how the timestamp of a syscall would be off?
- bechampion 10y agoI think an explanation would be PTRACING a process and tapping on its syscalls will always add some latency , for example time(process(open())) < time(ptrace(process(open))) if that makes sense ? , similar to selinux ... there's a cost to tapping syscalls.
- Hello71 10y agothey're absolutely inaccurate for the reason you mentioned, but they're also relatively inaccurate because not all of the program's execution is syscalls. regular program code runs at the same speed (more or less), but syscalls are made much slower so appear to take more time than they really do.