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=-2.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 89B74C433FF for ; Tue, 6 Aug 2019 21:14:47 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 554352173C for ; Tue, 6 Aug 2019 21:14:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="dOMaJTzo" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 554352173C 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-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=1UJWUaOOJJVwmebGWlM/SnE8OxgN9XA83/bm+bnYm+o=; b=dOMaJTzo660MulphD7JocLqF7 Gfk2bJySUJBEnh60mzZrh1QbOh2+qZDiW+/2RwhwDADfJGD6jfj0H5UpQiD5ysV1UgGo4zigQK9Lz DvuWqopbFssO5qH8L5Y2xV+m7lF4lsfWxD6RFsZj1ATvlSS+tHk3X1V+dLNiqUJk5DSe6nGRwRMmW +FF18SmsTY+Du4l1zT5Lrd6tIxTRBZ5M/0VK2FHDh3Uy8Bp+u3KN4fQHUWzcaSqYl0W6bVpEgg1qw DHa2RE5ccHYu1StKMUlZ+o2WZB5NJUX6AczE2DrYuo/lnI+ze43Q8VYxFkiBblyIZSY4mkr8LjYKS LXoEij15Q==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hv6n8-0004Ri-Q1; Tue, 06 Aug 2019 21:14:46 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hv6n5-0004RJ-LV for linux-arm-kernel@lists.infradead.org; Tue, 06 Aug 2019 21:14:45 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 019AC344; Tue, 6 Aug 2019 14:14:41 -0700 (PDT) Received: from [192.168.1.124] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2E8773F694; Tue, 6 Aug 2019 14:14:39 -0700 (PDT) Subject: Re: [PATCH] arm64: dts: allwinner: a64: Drop PMU node To: Vasily Khoruzhick , Harald Geyer References: <20190806140135.4739-1-anarsoul@gmail.com> <89402d22-d432-9551-e787-c8ede16dbe5f@arm.com> From: Robin Murphy Message-ID: <36e60078-7dd5-9c07-ffa1-6092d8c70fa8@arm.com> Date: Tue, 6 Aug 2019 22:14:39 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-GB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190806_141443_751110_F127F93B X-CRM114-Status: GOOD ( 15.88 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , devicetree , "Jared D . McNeill" , Maxime Ripard , Chen-Yu Tsai , Rob Herring , arm-linux Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2019-08-06 9:52 pm, Vasily Khoruzhick wrote: > On Tue, Aug 6, 2019 at 1:19 PM Harald Geyer wrote: >> >> Vasily Khoruzhick writes: >>> On Tue, Aug 6, 2019 at 7:35 AM Robin Murphy wrote: >>>> >>>> On 06/08/2019 15:01, Vasily Khoruzhick wrote: >>>>> Looks like PMU in A64 is broken, it generates no interrupts at all and >>>>> as result 'perf top' shows no events. >>>> >>>> Does something like 'perf stat sleep 1' at least count cycles correctly? >>>> It could well just be that the interrupt numbers are wrong... >>> >>> Looks like it does, at least result looks plausible: >> >> I'm using perf stat regularly (cache benchmarks) and it works fine. >> >> Unfortunately I wasn't aware that perf stat is a poor test for >> the interrupts part of the node, when I added it. So I'm not too >> surprised I got it wrong. >> >> However, it would be unfortunate if the node got removed completely, >> because perf stat would not work anymore. Maybe we can only remove >> the interrupts or just fix them even if the HW doesn't work? > > I'm not familiar with PMU driver. Is it possible to get it working > without interrupts? Yup - you get a grumpy message from the driver, it will refuse sampling events (the ones which weren't working anyway), and if you measure anything for long enough that a counter overflows you'll get wonky results. But for counting hardware events over relatively short periods it'll still do the job. Robin. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel