From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7DF31C00449 for ; Wed, 3 Oct 2018 09:26:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3887020835 for ; Wed, 3 Oct 2018 09:26:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3887020835 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727260AbeJCQNh (ORCPT ); Wed, 3 Oct 2018 12:13:37 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:48324 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726216AbeJCQNh (ORCPT ); Wed, 3 Oct 2018 12:13:37 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C31DE7A9; Wed, 3 Oct 2018 02:26:03 -0700 (PDT) Received: from [10.4.13.99] (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id AC3443F5B7; Wed, 3 Oct 2018 02:26:01 -0700 (PDT) Subject: Re: [PATCH v5 19/27] irqchip/gic-v3: Remove acknowledge loop To: Julien Thierry , linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, daniel.thompson@linaro.org, joel@joelfernandes.org, mark.rutland@arm.com, christoffer.dall@arm.com, james.morse@arm.com, catalin.marinas@arm.com, will.deacon@arm.com, Thomas Gleixner , Jason Cooper References: <1535471497-38854-1-git-send-email-julien.thierry@arm.com> <1535471497-38854-20-git-send-email-julien.thierry@arm.com> From: Marc Zyngier Organization: ARM Ltd Message-ID: Date: Wed, 3 Oct 2018 10:26:00 +0100 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <1535471497-38854-20-git-send-email-julien.thierry@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 28/08/18 16:51, Julien Thierry wrote: > Multiple interrupts pending for a CPU is actually rare. Doing an > acknowledge loop does not give much better performance or even can > deteriorate them. > > Do not loop when an interrupt has been acknowledged, just return > from interrupt and wait for another one to be raised. > > Tested-by: Daniel Thompson > Signed-off-by: Julien Thierry > Cc: Thomas Gleixner > Cc: Jason Cooper > Cc: Marc Zyngier > --- > drivers/irqchip/irq-gic-v3.c | 65 +++++++++++++++++++++----------------------- > 1 file changed, 31 insertions(+), 34 deletions(-) It would probably be valuable to do the same thing for GICv1/v2, where the MMIO access can be even more costly. In the meantime, I've queued this for 4.20. Thanks, M. -- Jazz is not dead. It just smells funny... From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc.zyngier@arm.com (Marc Zyngier) Date: Wed, 3 Oct 2018 10:26:00 +0100 Subject: [PATCH v5 19/27] irqchip/gic-v3: Remove acknowledge loop In-Reply-To: <1535471497-38854-20-git-send-email-julien.thierry@arm.com> References: <1535471497-38854-1-git-send-email-julien.thierry@arm.com> <1535471497-38854-20-git-send-email-julien.thierry@arm.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 28/08/18 16:51, Julien Thierry wrote: > Multiple interrupts pending for a CPU is actually rare. Doing an > acknowledge loop does not give much better performance or even can > deteriorate them. > > Do not loop when an interrupt has been acknowledged, just return > from interrupt and wait for another one to be raised. > > Tested-by: Daniel Thompson > Signed-off-by: Julien Thierry > Cc: Thomas Gleixner > Cc: Jason Cooper > Cc: Marc Zyngier > --- > drivers/irqchip/irq-gic-v3.c | 65 +++++++++++++++++++++----------------------- > 1 file changed, 31 insertions(+), 34 deletions(-) It would probably be valuable to do the same thing for GICv1/v2, where the MMIO access can be even more costly. In the meantime, I've queued this for 4.20. Thanks, M. -- Jazz is not dead. It just smells funny...