Date: Thu, 21 May 2009 09:49:57 -0700 From: Marcel Moolenaar <xcllnt@mac.com> To: FreeBSD PowerPC ML <freebsd-ppc@freebsd.org> Subject: [patch] __syncicache: eliminate D-cache flush Message-ID: <6C962FE0-657A-4072-B050-903D54C712D4@mac.com>
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All,
I'd like to commit the following change, which basically removes
the D-cache flush from syncicache. This gave me a 6% performance
improvement on my SMP xserve (but YMMV):
Index: sys/powerpc/powerpc/syncicache.c
===================================================================
--- sys/powerpc/powerpc/syncicache.c (revision 192134)
+++ sys/powerpc/powerpc/syncicache.c (working copy)
@@ -50,23 +50,14 @@
void
__syncicache(void *from, int len)
{
- int l, off;
- char *p;
+ char *p, *lim;
- off = (u_int)from & (cacheline_size - 1);
- l = len += off;
- p = (char *)from - off;
+ p = (char *)((uintptr_t)from & (cacheline_size - 1));
+ lim = (char *)from + len;
- do {
- __asm __volatile ("dcbst 0,%0" :: "r"(p));
- p += cacheline_size;
- } while ((l -= cacheline_size) > 0);
- __asm __volatile ("sync");
- p = (char *)from - off;
- do {
+ while (p < lim) {
__asm __volatile ("icbi 0,%0" :: "r"(p));
p += cacheline_size;
- } while ((len -= cacheline_size) > 0);
+ }
__asm __volatile ("sync; isync");
}
-
I tested a make buildworld/buildkernel and a make release. I can't
test the image because I'm having difficulty booting from the CD
(I think that's mostly related to using a serial console and none
of the standard Open Firmware key combinations works).
Can someone try and boot (and preferably go through a real install):
http://people.freebsd.org/~marcel/8.0-CURRENT-200905-powerpc-disc1.iso
In the mean time, I'll try a make buildworld across NFS to see if
we need to implement cpu_flush_dcache() to compensate...
--
Marcel Moolenaar
xcllnt@mac.com
help
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