[PATCH] Suggested FreeBSD merge

Matthew Dillon dillon at apollo.backplane.com
Sun Nov 14 10:24:15 PST 2004

:On Fri, Nov 12, 2004 at 01:39:13PM +0800, Xin LI wrote:
:> I think you would interest the patch attached.  This brings FreeBSD
:> rev. 1.10 of htonl.S and ntohl.S's changes by David O'Brien, which
:> is positive for application performance on 80486 and above.
:I'm thinking about providing something similiar to the library page
:MacOS X has. I forget the name, but the idea is to provide some pages
:mapped by the kernel to a fixed address with optimized code for the
:target CPU. Because of the static mapping, it doesn't have the penalty
:of Position Independent Code and also can be adjusted without changing
:the applications.

    I like the idea of a kernel-provided set of native procedures.  But
    we have to be very careful not to create a situation that will bite
    us in the ass.

    So, for example, I would never hard-code an actual fixed address.
    Instead I would take advantage of the fact that we are now in pure ELF
    environment and I would put some elf-loader glue in the kernel to
    resolve references to the kernel-supplied read-only mapping, or something
    like that, using a special ELF section.

					Matthew Dillon 
					<dillon at xxxxxxxxxxxxx>

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