Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761758Ab2KBK1m (ORCPT ); Fri, 2 Nov 2012 06:27:42 -0400 Received: from bear.ext.ti.com ([192.94.94.41]:40850 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750927Ab2KBK1k (ORCPT ); Fri, 2 Nov 2012 06:27:40 -0400 Message-ID: <50939FFE.9020401@ti.com> Date: Fri, 2 Nov 2012 15:57:10 +0530 From: Santosh Shilimkar User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120912 Thunderbird/15.0.1 MIME-Version: 1.0 To: Vincent Guittot CC: , , , , , , Subject: Re: [RFC 2/6] sched: add a new SD SHARE_POWERLINE flag for sched_domain References: <1349595838-31274-1-git-send-email-vincent.guittot@linaro.org> <1349595838-31274-3-git-send-email-vincent.guittot@linaro.org> <5088066D.7000907@ti.com> In-Reply-To: Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4935 Lines: 107 On Monday 29 October 2012 03:20 PM, Vincent Guittot wrote: > It looks like i need to describe more what > > On 29 October 2012 10:40, Vincent Guittot wrote: >> On 24 October 2012 17:17, Santosh Shilimkar wrote: >>> Vincent, >>> >>> Few comments/questions. >>> >>> >>> On Sunday 07 October 2012 01:13 PM, Vincent Guittot wrote: >>>> >>>> This new flag SD SHARE_POWERLINE reflects the sharing of the power rail >>>> between the members of a domain. As this is the current assumption of the >>>> scheduler, the flag is added to all sched_domain >>>> >>>> Signed-off-by: Vincent Guittot >>>> --- >>>> arch/ia64/include/asm/topology.h | 1 + >>>> arch/tile/include/asm/topology.h | 1 + >>>> include/linux/sched.h | 1 + >>>> include/linux/topology.h | 3 +++ >>>> kernel/sched/core.c | 5 +++++ >>>> 5 files changed, 11 insertions(+) >>>> >>>> diff --git a/arch/ia64/include/asm/topology.h >>>> b/arch/ia64/include/asm/topology.h >>>> index a2496e4..065c720 100644 >>>> --- a/arch/ia64/include/asm/topology.h >>>> +++ b/arch/ia64/include/asm/topology.h >>>> @@ -65,6 +65,7 @@ void build_cpu_to_node_map(void); >>>> | SD_BALANCE_EXEC \ >>>> | SD_BALANCE_FORK \ >>>> | SD_WAKE_AFFINE, \ >>>> + | arch_sd_share_power_line() \ >>>> .last_balance = jiffies, \ >>>> .balance_interval = 1, \ >>>> .nr_balance_failed = 0, \ >>>> diff --git a/arch/tile/include/asm/topology.h >>>> b/arch/tile/include/asm/topology.h >>>> index 7a7ce39..d39ed0b 100644 >>>> --- a/arch/tile/include/asm/topology.h >>>> +++ b/arch/tile/include/asm/topology.h >>>> @@ -72,6 +72,7 @@ static inline const struct cpumask *cpumask_of_node(int >>>> node) >>>> | 0*SD_PREFER_LOCAL \ >>>> | 0*SD_SHARE_CPUPOWER \ >>>> | 0*SD_SHARE_PKG_RESOURCES \ >>>> + | arch_sd_share_power_line() \ >>>> | 0*SD_SERIALIZE \ >>>> , \ >>>> .last_balance = jiffies, \ >>>> diff --git a/include/linux/sched.h b/include/linux/sched.h >>>> index 4786b20..74f2daf 100644 >>>> --- a/include/linux/sched.h >>>> +++ b/include/linux/sched.h >>>> @@ -862,6 +862,7 @@ enum cpu_idle_type { >>>> #define SD_WAKE_AFFINE 0x0020 /* Wake task to waking CPU >>>> */ >>>> #define SD_PREFER_LOCAL 0x0040 /* Prefer to keep tasks >>>> local to this domain */ >>>> #define SD_SHARE_CPUPOWER 0x0080 /* Domain members share cpu power >>>> */ >>>> +#define SD_SHARE_POWERLINE 0x0100 /* Domain members share power >>>> domain */ >>> >>> If you ignore the current use of SD_SHARE_CPUPOWER, isn't the meaning of >>> CPUPOWER and POWERLINE is same here. Just trying to understand the clear >>> meaning of this new flag. Have you not considered SD_SHARE_CPUPOWER >>> because it is being used for cpu_power and needs at least minimum two >>> domains ? SD_PACKING would have been probably more appropriate based >>> on the way it is being used in further series. >> >> CPUPOWER reflects the share of hw ressources between cores like for >> hyper threading. POWERLINE describes the fact that cores are sharing >> the same power line amore precisely the powergate. > > Sorry, the mail has been sent too early while I was writing it > > CPUPOWER reflects the share of hw ressources between cores like for > hyper threading. POWERLINE describes the fact that cores are sharing > the same power line and more precisely the same power gating. It looks > like I need to describe more precisely what i would mean with > SHARE_POWERLINE. > Yes. More description will help. I see bit of overlap POWERLINE flag with SD_SHARE_CPUPOWER and SD_SHARE_PKG_RESOURCES and hence the questions. > I don't want to use PACKING because it's more a behavior than a > feature. If cores can power gate independently (!SD_SHARE_POWERLINE), > packing small tasks is one interesting behavior but it may be not the > only one. I want to make a difference between the HW configuration and > the behavior we want to have above it > Fair enough. Thanks for clarification. Regards, Santosh -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/