[POWERPC] powerpc: Enable DEEPNAP power savings mode on 970MP
Without this patch, on an idle system I get:
cpu-power-0:21.638
cpu-power-1:27.102
cpu-power-2:29.343
cpu-power-3:25.784
Total: 103.8W
With this patch:
cpu-power-0:11.730
cpu-power-1:17.185
cpu-power-2:18.547
cpu-power-3:17.528
Total: 65.0W
If I lower HZ to 100, I can get it as low as:
cpu-power-0:10.938
cpu-power-1:16.021
cpu-power-2:17.245
cpu-power-3:16.145
Total: 60.2W
Another (older) Quad G5 went from 54W to 39W at HZ=250.
Coming back out of Deep Nap takes 40-70 cycles longer than coming back
from just Nap (which already takes quite a while). I don't think it'll
be a performance issue (interrupt latency on an idle system), but in
case someone does measurements feel free to report them.
Signed-off-by: Olof Johansson <olof@lixom.net>
Acked-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
index 95382f9..f02b402 100644
--- a/arch/powerpc/kernel/cputable.c
+++ b/arch/powerpc/kernel/cputable.c
@@ -41,6 +41,7 @@
#endif /* CONFIG_PPC32 */
#ifdef CONFIG_PPC64
extern void __setup_cpu_ppc970(unsigned long offset, struct cpu_spec* spec);
+extern void __setup_cpu_ppc970MP(unsigned long offset, struct cpu_spec* spec);
extern void __restore_cpu_ppc970(void);
#endif /* CONFIG_PPC64 */
@@ -221,7 +222,7 @@
.icache_bsize = 128,
.dcache_bsize = 128,
.num_pmcs = 8,
- .cpu_setup = __setup_cpu_ppc970,
+ .cpu_setup = __setup_cpu_ppc970MP,
.cpu_restore = __restore_cpu_ppc970,
.oprofile_cpu_type = "ppc64/970",
.oprofile_type = PPC_OPROFILE_POWER4,