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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id C518FC433FE for ; Thu, 10 Nov 2022 08:33:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Subject:Cc:To:From:Message-ID:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=4qGW8gA12PqwQzp4XzZxauDNslPmzZMsOOUmzORdIFE=; b=o4Rdcmif7gqwJ6 yTAagydLUvJcBB0pvPe2rQh6LNRCKtTEyu7aCdH2pbqg11OxX3GAHmIM6q9a+QgEHp9uiwsumOkmu JD0nwz1eKjtZ82zBAXKnNOm27SeRe/xMk3B/o5eVdvBvW7QVG8NQGhpxwR5WmO5/u7/NTzSymPJp2 WcXd1btmr3Bg/NlvLPepl+ezWQUGRnEQXve2yDIlKCYt893sZXkmBaBS7k5UZ07WqI0kAkPp3sWVs 5Z5ZEH9rm2Ba5TzxCUXlo5oxHsOM69U00D6M0dw31EgfND7B6FhJHonQy6n0b7uBsT3+I0AcgiSny klyQpwhoiCCAInLsSXWg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ot2yY-004H5b-6s; Thu, 10 Nov 2022 08:31:54 +0000 Received: from ams.source.kernel.org ([2604:1380:4601:e00::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ot2yU-004H4s-N9 for linux-arm-kernel@lists.infradead.org; Thu, 10 Nov 2022 08:31:52 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 55EFAB820F6; Thu, 10 Nov 2022 08:31:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 09339C433D6; Thu, 10 Nov 2022 08:31:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1668069108; bh=FTZ37ZZEVEs+TiNITnQUDC2fgV3ZHp8BzIxq1ELh2Uc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=ceqBPQ1z1DzdFP5DNoGCe197llXqC8iHcWxDXm5kKrVJHHNgKYk/VbDhmOV8AHLQo Goj3OPPmLxnsX0V1is0UeWkl4QYy3Vtnxypkyz4gvd1kP2fJyfJDbj/F4+dflIuJoW 9aqjSVvzS6+/l1WAK27LfoUBS004ybKHpIC3FbOXgncMH+0aZTYcU4EQQTbrGe/jvr smjz0e179+TdsF1uxZxdRqXfpbzHY7qkEU3ih2YQESunBqu5Ut+dgvF7jy6RVi+q4i 1LamVj6L4Qg/ZNsw0zNDYlU9RWAADlugkUEjkXaQRgbLVQZi5rHUt1SuFgk/qh01Ja Qxd1X3CwqyCAg== Received: from ip-185-104-136-29.ptr.icomera.net ([185.104.136.29] helo=wait-a-minute.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1ot2yP-0056PZ-Uk; Thu, 10 Nov 2022 08:31:46 +0000 Date: Thu, 10 Nov 2022 08:31:21 +0000 Message-ID: <87k043us6e.wl-maz@kernel.org> From: Marc Zyngier To: Ilya Dikariev Cc: Mark Rutland , Daniel Lezcano , Thomas Gleixner , Samuel Holland , Chen-Yu Tsai , Jernej =?UTF-8?B?xaBrcmFiZWM=?= , linux-sunxi@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] drivers/clocksource/arm_arch_timer: Tighten Allwinner arch timer workaround In-Reply-To: <20221109221049.4bf3c5bb@rosh> References: <20221109221049.4bf3c5bb@rosh> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") X-SA-Exim-Connect-IP: 185.104.136.29 X-SA-Exim-Rcpt-To: dikarill@b-tu.de, mark.rutland@arm.com, daniel.lezcano@linaro.org, tglx@linutronix.de, samuel@sholland.org, wens@csie.org, jernej.skrabec@gmail.com, linux-sunxi@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221110_003151_055219_83832993 X-CRM114-Status: GOOD ( 18.61 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, 09 Nov 2022 21:10:49 +0000, Ilya Dikariev wrote: > > As we know, the Allwinner A64 SoC has a buggy RCU time unit. The What is RCU? > workaround named UNKNOWN1 was not sufficient to cover some more buggy > bunches of this SoC. This workaround diminish the mask to 8 bits instead > of 9. > > An example run of timer test tool https://github.com/smaeul/timer-tools > on PinePhone device (owns the A64 SoC) gives following result on a non > patched kernel (cut off): > > Running parallel counter test... > 0: Failed after 5507 reads (0.003578 s) > 0: 0x0000000c8272cbf1 -> 0x0000000c8272ccff -> 0x0000000c8272cc0e ( 0.011 ms) > 2: Failed after 14518 reads (0.009248 s) > 2: 0x0000000c827513f1 -> 0x0000000c82751300 -> 0x0000000c8275140e ( -0.010 ms) > 3: Failed after 14112 reads (0.008730 s) > 3: 0x0000000c8274f3f2 -> 0x0000000c8274f300 -> 0x0000000c8274f40d ( -0.010 ms) > 1: Failed after 12030 reads (0.008409 s) > 1: 0x0000000c8274abf1 -> 0x0000000c8274acff -> 0x0000000c8274ac0f ( 0.011 ms) > 1: 0x0000000c827759f2 -> 0x0000000c82775aff -> 0x0000000c82775a0e ( 0.011 ms) > 0: 0x0000000c8277a9f2 -> 0x0000000c8277aaff -> 0x0000000c8277aa0d ( 0.011 ms) > 2: 0x0000000c8278f3f1 -> 0x0000000c8278f300 -> 0x0000000c8278f40e ( -0.010 ms) > 0: 0x0000000c82785ff2 -> 0x0000000c82784300 -> 0x0000000c8278600d ( -0.309 ms) > > After the proposed patch applied the test runs > correctly (~2 hours of testing with a tool above without fails) 2 hours seems like an incredibly small amount of time given that the existing workaround was believed to be correct. Run it continuously for a couple of weeks on several different machines with varying workloads and less us know the outcome. Thanks, M. -- Without deviation from the norm, progress is not possible. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel