From mboxrd@z Thu Jan 1 00:00:00 1970 From: sboyd@codeaurora.org (Stephen Boyd) Date: Mon, 28 Oct 2013 09:18:42 -0700 Subject: [tip:timers/core] ARM: Kconfig: allow full nohz CPU accounting In-Reply-To: <526DBEAA.4030707@linaro.org> References: <20131016121416.GD12773@localhost.localdomain> <20131018163740.GA21983@codeaurora.org> <526DBEAA.4030707@linaro.org> Message-ID: <526E8E62.7070700@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 10/27/13 18:32, Kevin Hilman wrote: > Hi Stephen, > > On 10/18/2013 09:37 AM, Stephen Boyd wrote: >> On 10/16, Frederic Weisbecker wrote: >>> On Thu, Oct 03, 2013 at 06:58:03AM -0700, tip-bot for Kevin Hilman wrote: >>>> Commit-ID: 31c1fc8187158cb80ccd57c19e024c55af901797 >>>> Gitweb: http://git.kernel.org/tip/31c1fc8187158cb80ccd57c19e024c55af901797 >>>> Author: Kevin Hilman >>>> AuthorDate: Mon, 16 Sep 2013 15:28:22 -0700 >>>> Committer: Frederic Weisbecker >>>> CommitDate: Mon, 30 Sep 2013 15:37:05 +0200 >>>> >>>> ARM: Kconfig: allow full nohz CPU accounting >>>> >>>> With the 64-bit requirement removed from VIRT_CPU_ACCOUNTING_GEN, >>>> allow ARM platforms to enable it. Since VIRT_CPU_ACCOUNTING_GEN is a >>>> dependency for full NO_HZ, this allows ARM platforms to enable full >>>> NO_HZ as well. >>> I realize that arm doesn't implement irq work raise. It hooks on the >>> timer to execute pending irq work. You'll need to implement arch_irq_work_raise() >>> and implement some sort of self IPI to trigger irq work. The full dynticks subsystem >>> relies on that to work correctly. It often use that to re-evaluate and possibly restart >>> the tick after scheduler, posix timer updates, etc... >>> >>> That notwithstanding that if you have no tick, tick based irq work can't >>> work. >>> >> Something like this? The only problem is that this latches on to >> the SMP support for IPIs. If CONFIG_SMP is disabled we won't get >> arch_irq_work_raise() but perhaps that isn't so big of a deal? Or >> we should think about exposing IPI support to UP systems on ARM. > Care to submit a proper patch for this to LAKML? or if you prefer I can > do it (keeping your authorship.) We need this for proper full NOHZ > support on ARM. Thanks. Sure no problem. Let me write up some sort of commit text and I'll send it off again. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation