Reducing system calls overhead

[Jack Jansen]

I don't think that the solution you pose for simple calls would
help anything. First, calls like getuid, getpid, etc. are very
rare, and, second, there's a much simpler solution for these calls:
just do the call the first time and cache the result.

For getpid() you would need some help from fork/vfork, but nothing
undoable.
This would get the same results, and even cheaper.

Now, two calls that *would* benefit from optimization are stat() and
ioctl().
>From some system call traces I've seen it showed that these calls
are done incredibly often: stat() by programs that first check
modes before they create a file; and ioctl() by all sorts of
shells, etc. that have command line editing.

Unfortunately the quick-entry system doesn't work here because both
these calls can block....

	Jack Jansen, jack at cwi.nl (or jack at mcvax.uucp)
	The shell is my oyster.