From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id 3FEBF67D9C for ; Thu, 5 Oct 2006 15:34:37 +1000 (EST) Subject: Re: [PATCH] powerpc: Enable DEEPNAP power savings mode on 970MP From: Benjamin Herrenschmidt To: Olof Johansson In-Reply-To: <20061004234141.749b13fb@localhost.localdomain> References: <20061004234141.749b13fb@localhost.localdomain> Content-Type: text/plain Date: Thu, 05 Oct 2006 15:34:24 +1000 Message-Id: <1160026464.22232.16.camel@localhost.localdomain> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org, paulus@samba.org, linux-kernel@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 > > > > 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