Why getpid() is not implemented in x86_64's vdso?

Asked Dec 26 '20 at 06:30

Active Dec 26 '20 at 10:02

Viewed 379 times

After glibc 2.25, glibc's getpid() wrapper no longer cache its result. However, on x86_64 vdso didn't provide getpid() function. Which means everytime getpid() is called, a syscall is triggered.

I am wondering why x86_64 vdso does not provide getpid() function (even on kernel 5.x).

edited Dec 26 '20 at 10:02

Rachid K.

4,490
3
11
30

asked Dec 26 '20 at 06:30

戴均維

3

Related: https://ipfs.io/ipfs/QmdA5WkDNALetBn4iFeSepHjdLGJdxPBwZyY47ir1bZGAK/comp/linux/getpid_caching.html – Ammar Faizi Dec 26 '20 at 14:27
2

If performance of `getpid` is that important for your application, it is likely that your application design is rather sub-optimal. – Maxim Egorushkin Dec 26 '20 at 15:19

Why getpid() is not implemented in x86_64's vdso?

0 Answers0