Subject: Re: amd64 syscall.c question
To: Blair Sadewitz <>
From: Andrew Doran <>
List: port-amd64
Date: 06/06/2007 21:01:44
On Wed, Jun 06, 2007 at 03:39:29PM -0400, Blair Sadewitz wrote:

> BTW, what is the operational distinction between syscall_plain() and
> syscall_fancy()?

Fancy handles tracing (like ktrace), plain does not. The syscall handler is
noted in struct mdproc and entered through an indirect call. For CPUs that
actually matter, indirect calls are more expensive than a couple of simple
test+branch pairs, and maintaining 2x the number of syscall paths is a pain.
So they should be merged.