* [PATCH] powerpc: Enable DEEPNAP power savings mode on 970MP
@ 2006-10-05 4:41 Olof Johansson
2006-10-05 5:34 ` Benjamin Herrenschmidt
2006-10-05 19:25 ` Michael Buesch
0 siblings, 2 replies; 4+ messages in thread
From: Olof Johansson @ 2006-10-05 4:41 UTC (permalink / raw)
To: paulus; +Cc: linuxppc-dev, linux-kernel
Hi,
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>
Index: linux-2.6/arch/powerpc/kernel/cpu_setup_ppc970.S
===================================================================
--- linux-2.6.orig/arch/powerpc/kernel/cpu_setup_ppc970.S
+++ linux-2.6/arch/powerpc/kernel/cpu_setup_ppc970.S
@@ -83,6 +83,22 @@ _GLOBAL(__setup_cpu_ppc970)
rldimi r0,r11,52,8 /* set NAP and DPM */
li r11,0
rldimi r0,r11,32,31 /* clear EN_ATTN */
+ b load_hids /* Jump to shared code */
+
+
+_GLOBAL(__setup_cpu_ppc970MP)
+ /* Do nothing if not running in HV mode */
+ mfmsr r0
+ rldicl. r0,r0,4,63
+ beqlr
+
+ mfspr r0,SPRN_HID0
+ li r11,0x15 /* clear DOZE and SLEEP */
+ rldimi r0,r11,52,6 /* set DEEPNAP, NAP and DPM */
+ li r11,0
+ rldimi r0,r11,32,31 /* clear EN_ATTN */
+
+load_hids:
mtspr SPRN_HID0,r0
mfspr r0,SPRN_HID0
mfspr r0,SPRN_HID0
Index: linux-2.6/arch/powerpc/kernel/cputable.c
===================================================================
--- linux-2.6.orig/arch/powerpc/kernel/cputable.c
+++ linux-2.6/arch/powerpc/kernel/cputable.c
@@ -41,6 +41,7 @@ extern void __setup_cpu_745x(unsigned lo
#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 @@ struct cpu_spec cpu_specs[] = {
.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,
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] powerpc: Enable DEEPNAP power savings mode on 970MP
2006-10-05 4:41 [PATCH] powerpc: Enable DEEPNAP power savings mode on 970MP Olof Johansson
@ 2006-10-05 5:34 ` Benjamin Herrenschmidt
2006-10-05 14:21 ` Olof Johansson
2006-10-05 19:25 ` Michael Buesch
1 sibling, 1 reply; 4+ messages in thread
From: Benjamin Herrenschmidt @ 2006-10-05 5:34 UTC (permalink / raw)
To: Olof Johansson; +Cc: linuxppc-dev, paulus, linux-kernel
On Wed, 2006-10-04 at 23:41 -0500, Olof Johansson wrote:
> Hi,
>
> 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.
Isn't deep nap supposed to only get entered from F/4 which we never
use ?
Ben confused...
>
> Signed-off-by: Olof Johansson <olof@lixom.net>
>
>
>
> Index: linux-2.6/arch/powerpc/kernel/cpu_setup_ppc970.S
> ===================================================================
> --- linux-2.6.orig/arch/powerpc/kernel/cpu_setup_ppc970.S
> +++ linux-2.6/arch/powerpc/kernel/cpu_setup_ppc970.S
> @@ -83,6 +83,22 @@ _GLOBAL(__setup_cpu_ppc970)
> rldimi r0,r11,52,8 /* set NAP and DPM */
> li r11,0
> rldimi r0,r11,32,31 /* clear EN_ATTN */
> + b load_hids /* Jump to shared code */
> +
> +
> +_GLOBAL(__setup_cpu_ppc970MP)
> + /* Do nothing if not running in HV mode */
> + mfmsr r0
> + rldicl. r0,r0,4,63
> + beqlr
> +
> + mfspr r0,SPRN_HID0
> + li r11,0x15 /* clear DOZE and SLEEP */
> + rldimi r0,r11,52,6 /* set DEEPNAP, NAP and DPM */
> + li r11,0
> + rldimi r0,r11,32,31 /* clear EN_ATTN */
> +
> +load_hids:
> mtspr SPRN_HID0,r0
> mfspr r0,SPRN_HID0
> mfspr r0,SPRN_HID0
> Index: linux-2.6/arch/powerpc/kernel/cputable.c
> ===================================================================
> --- linux-2.6.orig/arch/powerpc/kernel/cputable.c
> +++ linux-2.6/arch/powerpc/kernel/cputable.c
> @@ -41,6 +41,7 @@ extern void __setup_cpu_745x(unsigned lo
> #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 @@ struct cpu_spec cpu_specs[] = {
> .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,
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] powerpc: Enable DEEPNAP power savings mode on 970MP
2006-10-05 5:34 ` Benjamin Herrenschmidt
@ 2006-10-05 14:21 ` Olof Johansson
0 siblings, 0 replies; 4+ messages in thread
From: Olof Johansson @ 2006-10-05 14:21 UTC (permalink / raw)
To: Benjamin Herrenschmidt; +Cc: linuxppc-dev, paulus, linux-kernel
On Thu, 05 Oct 2006 15:34:24 +1000 Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
> Isn't deep nap supposed to only get entered from F/4 which we never
> use ?
>
> Ben confused...
Nope.
The User Manual clearly talks about going in/out of deep nap from the
different powertune frequencies, see for example section 6.4.2 and 9.4.2.
-Olof
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] powerpc: Enable DEEPNAP power savings mode on 970MP
2006-10-05 4:41 [PATCH] powerpc: Enable DEEPNAP power savings mode on 970MP Olof Johansson
2006-10-05 5:34 ` Benjamin Herrenschmidt
@ 2006-10-05 19:25 ` Michael Buesch
1 sibling, 0 replies; 4+ messages in thread
From: Michael Buesch @ 2006-10-05 19:25 UTC (permalink / raw)
To: Olof Johansson; +Cc: linuxppc-dev, paulus, linux-kernel
On Thursday 05 October 2006 06:41, Olof Johansson wrote:
> Hi,
>
> 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>
I am running DEEPNAP on my Quad since quite some time and I
did not see any problems.
It saves quite a bit of power (I think it was about 20W for me when
I measured it)
That's really worth it.
--
Greetings Michael.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2006-10-05 19:57 UTC | newest]
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2006-10-05 4:41 [PATCH] powerpc: Enable DEEPNAP power savings mode on 970MP Olof Johansson
2006-10-05 5:34 ` Benjamin Herrenschmidt
2006-10-05 14:21 ` Olof Johansson
2006-10-05 19:25 ` Michael Buesch
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