Jeff Roberson jroberson at
Wed Nov 5 01:40:32 PST 2003

On Wed, 5 Nov 2003, David Xu wrote:

> Jun Su wrote:
> >I noticed that Jeff Roberson implement this already. Is whi will be commit?
> >
> >
> >I google this because I found this feature is listed in the list of Kernel Improvement of WindowsXP. :-)
> >
> >Thanks,
> >Jun Su
> >
> >
> >
> I have almost done this experiment about 10 months ago.
> The patch is out of date and still not complete.
> Also it can give you some performance improve, but I think too many
> things need to be changed,
> and this really makes user ret code very dirty, some syscalls, for
> example, pipe() can not use
> this fast syscall, becaues pipe() seems using two registers to return
> file handle, the performance gain
> is immediately lost when the assemble code becomes more complex. I don't
> think this hack is worth
> to do on IA32, I heard AMD has different way to support fast syscall,
> that may already in FreeBSD
> AMD 64 branch.

This works with every syscall.  I have a patch in perforce that doesn't
require any changes to userret().  The performance gain is not so
substantial for most things but I feel that it is worth it.  Mini is
probably going to finish this up over the next week or so.


> David Xu
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