Jeff Garzik wrote:
> > PS: Because of usage of prefetch in include/linux/list.h, the
> > memory prefetch is triggered 137 times on my configuration...
> We need to merge in __builtin_prefetch support into the kernel,
> because gcc 3.1 recently got support for it.  It would be nice at
> least for future prefetch-related patches to perhaps call
> __builtin_prefetch, and have the headers substitute a prefetch if
> the compiler does not support it.

OK, I added this suggestion -- it changes compiler.h to look out for
gcc-3.1 and then set macros for __builtin_prefetch.
But in order to get gcc 3.1 to issue prefetches, the -mcpu (and/or
-march?) must be set to pentium3 or pentium4 (same applies for AMD
athlons).

There's one minor nit to this:
"copy_to_user" has declared the parameter "from" as const and then does
a prefetch on "from".... This produces a warning:

/usr/src/linux-2.4.17-mine/include/asm/uaccess.h: In function
`__constant_copy_to_user':
/usr/src/linux-2.4.17-mine/include/asm/uaccess.h:549: warning: passing
arg 1 of `__builtin_prefetch' discards qualifiers from pointer target
type

How can I resolve this ?

Greetings,
raY
-- 
---------------------------------------------------------------
Rainer Keller           Mail: Keller@hlrs.de
Allmandring 30          WWW: http://www.hlrs.de/people/keller
70550 Stuttgart         Tel. 0711 / 685 5858