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=-3.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 24129C33C9E for ; Tue, 28 Jan 2020 12:01:07 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D26712173E for ; Tue, 28 Jan 2020 12:01:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="aSc5fKvB" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D26712173E Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=amazon.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 68A6A6B0003; Tue, 28 Jan 2020 07:01:06 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 63AB46B0006; Tue, 28 Jan 2020 07:01:06 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5516B6B0007; Tue, 28 Jan 2020 07:01:06 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0103.hostedemail.com [216.40.44.103]) by kanga.kvack.org (Postfix) with ESMTP id 3E0DC6B0003 for ; Tue, 28 Jan 2020 07:01:06 -0500 (EST) Received: from smtpin12.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with SMTP id 018DD180AD804 for ; Tue, 28 Jan 2020 12:01:06 +0000 (UTC) X-FDA: 76426902132.12.top21_7df21e4bcc10a X-HE-Tag: top21_7df21e4bcc10a X-Filterd-Recvd-Size: 5044 Received: from smtp-fw-6001.amazon.com (smtp-fw-6001.amazon.com [52.95.48.154]) by imf19.hostedemail.com (Postfix) with ESMTP for ; Tue, 28 Jan 2020 12:01:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1580212866; x=1611748866; h=from:to:cc:subject:date:message-id:in-reply-to: mime-version; bh=G4XawBinOQE3v9IrgHKbrUqOdbum+3a/Cn7jH1Qi8Yw=; b=aSc5fKvB8YePM3uNCu1NRKIj2hhFv7p3skrYTQ2WuyOdXOiM1RHgyeB5 Q8NXhVc4ZedCJNtphX7IlP+b8Psa6i9hFAQvrywf7ANJtTdUFqtf8O5NL +eObG9FEDbYZg6VlTXHL3S7Yl8poCzNgUltNoMf+wLy1JZiFEc/PZG1ui U=; IronPort-SDR: eKQ9cgKWSjxfguOEiVl1w4CH1plajgwFhyokzCeQzCrOWS6XGUcwATYiT8fVCgmuR6xPMSMWRk OwuzHAQstfbQ== X-IronPort-AV: E=Sophos;i="5.70,373,1574121600"; d="scan'208";a="15092337" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-1d-9ec21598.us-east-1.amazon.com) ([10.43.8.6]) by smtp-border-fw-out-6001.iad6.amazon.com with ESMTP; 28 Jan 2020 12:01:04 +0000 Received: from EX13MTAUEA002.ant.amazon.com (iad55-ws-svc-p15-lb9-vlan3.iad.amazon.com [10.40.159.166]) by email-inbound-relay-1d-9ec21598.us-east-1.amazon.com (Postfix) with ESMTPS id E9ED3A1F50; Tue, 28 Jan 2020 12:00:56 +0000 (UTC) Received: from EX13D31EUA001.ant.amazon.com (10.43.165.15) by EX13MTAUEA002.ant.amazon.com (10.43.61.77) with Microsoft SMTP Server (TLS) id 15.0.1236.3; Tue, 28 Jan 2020 12:00:56 +0000 Received: from u886c93fd17d25d.ant.amazon.com (10.43.161.117) by EX13D31EUA001.ant.amazon.com (10.43.165.15) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Tue, 28 Jan 2020 12:00:46 +0000 From: To: CC: , , SeongJae Park , , , , , , , , , , , , , , , , , , Peter Zijlstra , "Ingo Molnar" , Mark Rutland , "Alexander Shishkin" , Jiri Olsa , Namhyung Kim Subject: Re: Re: [PATCH v2 0/9] Introduce Data Access MONitor (DAMON) Date: Tue, 28 Jan 2020 13:00:33 +0100 Message-ID: <20200128120033.27016-1-sjpark@amazon.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <41BBD985-4B3D-4F87-B69D-D8CFE6EC0EBE@lca.pw> (raw) MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.43.161.117] X-ClientProxiedBy: EX13D37UWA004.ant.amazon.com (10.43.160.23) To EX13D31EUA001.ant.amazon.com (10.43.165.15) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: To: Qian Cai On Tue, 28 Jan 2020 06:20:29 -0500 Qian Cai wrote: > > > > On Jan 28, 2020, at 5:50 AM, sjpark@amazon.com wrote: > > > > For the comments from perf maintainers, I added Steven Rostedt and Arnaldo > > Carvalho de Melo first, but I might missed someone. If you recommend some more > > people, I will add them to recipients. > > > > I made DAMON as a new subsystem because I think no existing subsystem fits well > > to be a base of DAMON, due to DAMON's unique goals and mechanisms described > > below in the original cover letter. > > > > The existing subsystem that most similar to DAMON might be 'mm/page_idle.c'. > > However, there are many conceptual differences with DAMON. One biggest > > difference I think is the target. 'page_idle' deals with physical page frames > > while DAMON deals with virtual address of specific processes. > > > > Nevertheless, if you have some different opinion, please let me know. > > I thought everyone should know to go to the MAINTAINERS file and search PERFORMANCE EVENTS SUBSYSTEM. I worried whether it could be a bother to send the mail to everyone in the section, but seems it was an unnecessary worry. Adding those to recipients. You can get the original thread of this patchset from https://lore.kernel.org/linux-mm/20200128085742.14566-1-sjpark@amazon.com/ > > It might be difficult but there is a perf subcommand for some subsystems like sched: tracing/measuring of scheduler actions and latencies. Seems like you are suggesting to implement the DAMON's core logic as a subcommand of perf in user space. Because DAMON's logic inherently require frequent interaction with privileged features that need to be done inside the kernel space, I think it will incur frequent context switch and might not fulfill its performance requirement. As far as I understand, we normally add a data source in the kernel and implement sophisticated handlings or visualizations in the perf. I think DAMON is a source of a new primitive data (data access pattern). Thanks, SeongJae Park