From mboxrd@z Thu Jan 1 00:00:00 1970 From: santosh.shilimkar@ti.com (Santosh Shilimkar) Date: Fri, 21 Dec 2012 15:38:02 +0530 Subject: [RFC PATCH 0/5] clockevents: decouple broadcast mechanism from drivers In-Reply-To: <1355832418-31692-1-git-send-email-mark.rutland@arm.com> References: <1355832418-31692-1-git-send-email-mark.rutland@arm.com> Message-ID: <50D43502.1070402@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Mark, On Tuesday 18 December 2012 05:36 PM, Mark Rutland wrote: > In some SMP systems, cpu-local timers may stop delivering interrupts > when in low power states, or not all CPUs may have local timers. To > support these systems we have a mechanism for broadcasting timer ticks > to other CPUs. This mechanism relies on the struct > clock_event_device::broadcast function pointer, which is a > driver-specific mechanism for broadcasting ticks to other CPUs. > > As the broadcast mechanism is architecture-specific, placing the > broadcast function on struct clock_event_device ties each driver to a > single architecture. Additionally the driver or architecture backend > must handle the routing of broadcast ticks to the correct > clock_event_device, leading to duplication of the list of active > clock_event_devices. > > These patches introduce a generic mechanism for handling the receipt of > timer broadcasts, and an optional architecture-specific broadcast > function which allows drivers to be decoupled from a particular > architecture will retaining support for timer tick broadcasts. These > mechanisms are wired up for the arm port, and have been boot-tested on a > pandaboard. > Apart from the relevant comments given against couple of patches and Stephen's printk string comment, the series looks pretty good to me. I have tested the series with CPUIdle where the broadcast is actually used actively. So feel free to add, Reviewed-tested-by: Santosh Shilimkar From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751989Ab2LUKHr (ORCPT ); Fri, 21 Dec 2012 05:07:47 -0500 Received: from arroyo.ext.ti.com ([192.94.94.40]:57239 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751429Ab2LUKHj (ORCPT ); Fri, 21 Dec 2012 05:07:39 -0500 Message-ID: <50D43502.1070402@ti.com> Date: Fri, 21 Dec 2012 15:38:02 +0530 From: Santosh Shilimkar User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Mark Rutland CC: , , , , , , , Subject: Re: [RFC PATCH 0/5] clockevents: decouple broadcast mechanism from drivers References: <1355832418-31692-1-git-send-email-mark.rutland@arm.com> In-Reply-To: <1355832418-31692-1-git-send-email-mark.rutland@arm.com> 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 Mark, On Tuesday 18 December 2012 05:36 PM, Mark Rutland wrote: > In some SMP systems, cpu-local timers may stop delivering interrupts > when in low power states, or not all CPUs may have local timers. To > support these systems we have a mechanism for broadcasting timer ticks > to other CPUs. This mechanism relies on the struct > clock_event_device::broadcast function pointer, which is a > driver-specific mechanism for broadcasting ticks to other CPUs. > > As the broadcast mechanism is architecture-specific, placing the > broadcast function on struct clock_event_device ties each driver to a > single architecture. Additionally the driver or architecture backend > must handle the routing of broadcast ticks to the correct > clock_event_device, leading to duplication of the list of active > clock_event_devices. > > These patches introduce a generic mechanism for handling the receipt of > timer broadcasts, and an optional architecture-specific broadcast > function which allows drivers to be decoupled from a particular > architecture will retaining support for timer tick broadcasts. These > mechanisms are wired up for the arm port, and have been boot-tested on a > pandaboard. > Apart from the relevant comments given against couple of patches and Stephen's printk string comment, the series looks pretty good to me. I have tested the series with CPUIdle where the broadcast is actually used actively. So feel free to add, Reviewed-tested-by: Santosh Shilimkar