From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752559AbbLRK22 (ORCPT ); Fri, 18 Dec 2015 05:28:28 -0500 Received: from foss.arm.com ([217.140.101.70]:38968 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751626AbbLRK20 (ORCPT ); Fri, 18 Dec 2015 05:28:26 -0500 Subject: Re: [PATCH v4 05/12] arm-cci: PMU: Add support for transactions To: Peter Zijlstra References: <1450374559-23315-1-git-send-email-suzuki.poulose@arm.com> <1450374559-23315-6-git-send-email-suzuki.poulose@arm.com> <20151217184255.GI6344@twins.programming.kicks-ass.net> Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, mark.rutland@arm.com, punit.agrawal@arm.com, arm@kernel.org From: "Suzuki K. Poulose" Message-ID: <5673DFC7.6060406@arm.com> Date: Fri, 18 Dec 2015 10:28:23 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <20151217184255.GI6344@twins.programming.kicks-ass.net> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 17/12/15 18:42, Peter Zijlstra wrote: > On Thu, Dec 17, 2015 at 05:49:12PM +0000, Suzuki K. Poulose wrote: >> We keep track of only the 'ADD' transactions. While we are in a >> transaction, we keep track of the indices allocated for the events >> and delay the following operations until the transaction is committed. >> 1) Programming the event on the counter >> 2) Enabling the counter >> 3) Setting the period for the event. > > So that's not really what the txn interface is for, its meant to > amortize event scheduling. OK > > The above doesn't look like it has a failure case, in which case you can > achieve the same simpler, using pmu::pmu_{dis,en}able(). > I thought about that, but was not sure if pmu->stop() is guaranteed to be called on all the events scheduled on the PMU when we pmu::pmu_disable(). Is it ? Thanks for the quick response. Suzuki From mboxrd@z Thu Jan 1 00:00:00 1970 From: Suzuki.Poulose@arm.com (Suzuki K. Poulose) Date: Fri, 18 Dec 2015 10:28:23 +0000 Subject: [PATCH v4 05/12] arm-cci: PMU: Add support for transactions In-Reply-To: <20151217184255.GI6344@twins.programming.kicks-ass.net> References: <1450374559-23315-1-git-send-email-suzuki.poulose@arm.com> <1450374559-23315-6-git-send-email-suzuki.poulose@arm.com> <20151217184255.GI6344@twins.programming.kicks-ass.net> Message-ID: <5673DFC7.6060406@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 17/12/15 18:42, Peter Zijlstra wrote: > On Thu, Dec 17, 2015 at 05:49:12PM +0000, Suzuki K. Poulose wrote: >> We keep track of only the 'ADD' transactions. While we are in a >> transaction, we keep track of the indices allocated for the events >> and delay the following operations until the transaction is committed. >> 1) Programming the event on the counter >> 2) Enabling the counter >> 3) Setting the period for the event. > > So that's not really what the txn interface is for, its meant to > amortize event scheduling. OK > > The above doesn't look like it has a failure case, in which case you can > achieve the same simpler, using pmu::pmu_{dis,en}able(). > I thought about that, but was not sure if pmu->stop() is guaranteed to be called on all the events scheduled on the PMU when we pmu::pmu_disable(). Is it ? Thanks for the quick response. Suzuki