On Sun, 2 Feb 2025 07:22:08 +0000 Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > On Sat, Feb 01, 2025 at 10:22:08PM -0500, Steven Rostedt wrote: > > And before seeing Peter's use of yield(), I was reluctant to use it for > > the very same reasons you mentioned above. In my test programs, I was > > simply using getuid(), as that was one of the quickest syscalls. > > Is getuid() guaranteed to issue a syscall? It feels like the kind of > information that a tricksy libc could cache. Traditionally, I think > we've used getppid() as the canonical "very cheap syscall" as no layer > can cache that information. Maybe that was what I used. Can't remember. And I think I even open coded it using syscall() to not even rely on glibc. -- Steve
