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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 51FC2C43603 for ; Tue, 17 Dec 2019 17:01:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 19D5221835 for ; Tue, 17 Dec 2019 17:01:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=lechnology.com header.i=@lechnology.com header.b="gtbQJaic" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727529AbfLQRBd (ORCPT ); Tue, 17 Dec 2019 12:01:33 -0500 Received: from vern.gendns.com ([98.142.107.122]:35790 "EHLO vern.gendns.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726402AbfLQRBd (ORCPT ); Tue, 17 Dec 2019 12:01:33 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lechnology.com; s=default; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To:Subject:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=y7ZEAcmZPxFwg+aGOU54UCujclnLtD57QbAxYvqOMRQ=; b=gtbQJaictnRaTNkCxdck5VVg2H LGqleXJD3bKMyrPr2ARsd9cPSVspytbXmTApXBo063i9jieYAXn426jEWKo6Zi1c1H+kiuoqmTLT4 yab2SEEa/7iruaUEfF8slxX3lUJEvX16T330+qjVUEQLDTZpYCNCkxcSVs+zcUtxj0q7JU1jbeiiO 7LYlVP8962lr+Kec4YHd4TF7MvEvOWFjfH1kSRHIw/GLB2j/M76CSczf+kT1yJw2rjDbM5qmZXdBJ so5oaj3ZmDD6fxreuqGJ3reCn47VUo9t/EIXS3MxhaTl7PQMr4muVJl2PK2z8hIF/EWHjfWOAF2+o SQuOrvxg==; Received: from [2600:1700:4830:165f::fb2] (port=57660) by vern.gendns.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.92) (envelope-from ) id 1ihGDx-0002LF-EA; Tue, 17 Dec 2019 12:01:29 -0500 Subject: Re: [PATCH 1/3] clocksource: davinci: work around a clocksource problem on dm365 SoC To: Bartosz Golaszewski Cc: Sekhar Nori , Daniel Lezcano , Thomas Gleixner , Kevin Hilman , Linux ARM , Linux Kernel Mailing List , Bartosz Golaszewski References: <20191213162453.15691-1-brgl@bgdev.pl> <20191213162453.15691-2-brgl@bgdev.pl> From: David Lechner Message-ID: Date: Tue, 17 Dec 2019 11:01:28 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - vern.gendns.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - lechnology.com X-Get-Message-Sender-Via: vern.gendns.com: authenticated_id: davidmain+lechnology.com/only user confirmed/virtual account not confirmed X-Authenticated-Sender: vern.gendns.com: davidmain@lechnology.com X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/17/19 2:00 AM, Bartosz Golaszewski wrote: > pon., 16 gru 2019 o 18:58 David Lechner napisał(a): >> >>> >>> +static unsigned int davinci_clocksource_tim32_mode; >> >> static unsigned bool davinci_clocksource_initialized; >> >>> + >>> static struct davinci_clockevent * >>> to_davinci_clockevent(struct clock_event_device *clockevent) >>> { >>> @@ -94,7 +96,7 @@ static void davinci_tim12_shutdown(void __iomem *base) >>> * halves. In this case TIM34 runs in periodic mode and we must >>> * not modify it. >>> */ >>> - tcr |= DAVINCI_TIMER_ENAMODE_PERIODIC << >>> + tcr |= davinci_clocksource_tim32_mode << >>> DAVINCI_TIMER_ENAMODE_SHIFT_TIM34; >> >> if (davinci_clocksource_initialized) >> tcr |= DAVINCI_TIMER_ENAMODE_PERIODIC << >> DAVINCI_TIMER_ENAMODE_SHIFT_TIM34; > > I thought about doing this initially, but then figured this code would > be called a lot, so why not avoid branching and just store the right > value? Alternatively we can do: > > if (likely(davinci_clocksource_initialized) > .... > Unless there is a measurable performance difference, I think it would be better with if/likely.