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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 62AC4C433F5 for ; Wed, 27 Oct 2021 08:06:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4A6C9610E5 for ; Wed, 27 Oct 2021 08:06:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240752AbhJ0IJO (ORCPT ); Wed, 27 Oct 2021 04:09:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:44876 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239150AbhJ0IJF (ORCPT ); Wed, 27 Oct 2021 04:09:05 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 4E658610C7; Wed, 27 Oct 2021 08:06:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1635322000; bh=R6npbyugMJ+bx1oeZuErmLo4Jh44Cv++S1JLqSBanos=; h=From:To:Cc:Subject:Date:In-Reply-To:From; b=pHrzvdXHYJhNqidAVW5XeItr4Df2lXPI8YXYcvXqhguVR1g0jM1UAw/8IHLCoII+R RwECQrjvFTNZ+ipvoRujdwg5j8J/CTfpGUz0e1BKmmfPVH3Fd9l7eKxsg2Nc1utxJz 4eRFkh7ZbPWewIUcCRHO+191vL+8fUE8xBjcMwMPTCZsnRImiq7I7M4t5FkgNtYRAi K8qC+WEGL3GijHj0WvM4do15Riqn7PsYggoh9MyK1IixOwkEU0WwRfZI8OH95wQ4OB hW/cHQ8danQvKFeQBQV6OqqI9gBJPO1dihGAXRl7+3odk4TxFownYtFFAaZhDrBtmg CCb8BpJwYRO5Q== From: SeongJae Park To: Xiongfeng Wang Cc: sj@kernel.org, Kefeng Wang , Linux Kernel Mailing List Subject: Re: DAMON: problems when running DAMON on ARM64 with 'transparent_hugepage' enabled Date: Wed, 27 Oct 2021 08:06:36 +0000 Message-Id: <20211027080636.14886-1-sj@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Xiongfeng, On Wed, 27 Oct 2021 14:14:57 +0800 Xiongfeng Wang wrote: > Sorry, I forgot to Cc the maillist. Cc it in this mail. > > On 2021/10/27 10:19, Xiongfeng Wang wrote: > > Hi SeongJae, > > > > Sorry to disturb you. It's just that I came across some problems when running > > DAMON, but still didn't find the solution after several days. You're not disturbing but helping me! Please don't say so! :) > > > > A short description is that the result of DAMON is not as expected when running > > on ARM64 with 'transparent_hugepage' enabled. But the result is correct when > > 'transparent_hugepage' is disabled. > > > > The following are the steps I came across the problems. > > 1. Firstly, I use 'damo record' to sample the 'stairs' demo. > > damo record "./masim ./configs/stairs.cfg" > > 2. Then I use 'damo report' to show the results. > > damo report heats --address_range xxx xxx --time_range xxx xxx --heatmap > > stdout --stdout_heatmap_color emotion > > The result doesn't show like a stair. I wrote a userspace demo to access a > > certain address range in loop and use DAMON to sample the demo. I added > > trace_print in 'damon_va_check_access()' and found out the pages in the address > > range are not always detected as accessed, which is not expected. When I disable > > transparent_hugepage by chance, the pages are marked as accessed. Then I test > > the 'stairs' demo again, the result is correct. It seems that, only when > > transparent_hugepage' is disabled, the access check works. I don't know where > > the bug is, the software or the hardware ? Appreciate it if you have time to > > reply. Thanks ! Thank you for this report! I have a theory, but would like to test first. Will check and get back to you soon. Thanks, SJ > > > > Thanks, > > Xiongfeng