How to comfirm whether __GI___clock_gettime() implemented as fast system call or not on x86_64 platform with Linux 4.19.84?

[孙世龙 sunshilong]

Hi, list

How to comfirm whether __GI___clock_gettime() implemented as fast
system call or not on x86_64 platform with Linux 4.19.84?
Here is some related backtrace log(hope there is some hint on this question):

(gdb) bt
#0  0x00007ffc41da89fa in ?? ()
#1  0x00007fa90785aaf0 in ?? ()
#2  0x00007fa905a16876 in __GI___clock_gettime (clock_id=0,
tp=0x7fa90785aac0) at ../sysdeps/unix/clock_gettime.c:115

Thank you for your attention to this matter.