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From: jack@cwi.nl (Jack Jansen)
Newsgroups: comp.unix.wizards,comp.os.misc
Subject: Re: Reducing system calls overhead
Message-ID: <7622@boring.cwi.nl>
Date: 26 Aug 88 12:45:31 GMT
References: <21606@ccicpg.UUCP>
Sender: news@cwi.nl
Organization: AMOEBA project, CWI, Amsterdam
Lines: 21

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@cwi.nl (or jack@mcvax.uucp)
	The shell is my oyster.