From nobody Fri Dec 19 03:07:17 2025 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4F47CEE57DF for ; Mon, 11 Sep 2023 04:59:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233799AbjIKE7b (ORCPT ); Mon, 11 Sep 2023 00:59:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40768 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233756AbjIKE7S (ORCPT ); Mon, 11 Sep 2023 00:59:18 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2D68A138; Sun, 10 Sep 2023 21:59:14 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 29486C433CB; Mon, 11 Sep 2023 04:59:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1694408353; bh=yCdyENSSr2jBoqcU5uuhQp9Eg5ZiZzpyIfgAEWQFG08=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IqHzNhQypANFa8iW43c8T+CdTyJNbZILeHGR5vSckO9OyBoFNScts3NkhNUB0hUdK Rx5bC7TPP6c1kPbTEQm4UdifFD22iGQnZOYHwLiu6/w9NW3rAlGLD3u3xc2w32aOoi Nwc02GNkWg4NlNb9IM0GaoGG0vBlM1yRLDmB0t9ggDMobW8Qees4i9hw4wfPsBX+rL 9ReNouLD2afycjPERmYjFbmeVk/RljkfbhU+Oj9GNhovKG9UKWU0/PnHfb8K6FMVBK gyc0JMX3jmy2dgaPh5Fktf3uJRTXqchjoXp1EoKv+dZhBQwxh5fiW9XEZVHusV6w5j ZNfpLBdyi3K5g== From: SeongJae Park To: Andrew Morton Cc: SeongJae Park , Jonathan Corbet , damon@lists.linux.dev, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/2] Docs/admin-guide/mm/damon/usage: document damos_before_apply tracepoint Date: Mon, 11 Sep 2023 04:59:08 +0000 Message-Id: <20230911045908.97649-3-sj@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230911045908.97649-1-sj@kernel.org> References: <20230911045908.97649-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Document damos_before_apply tracepoint on the usage document. Signed-off-by: SeongJae Park --- Documentation/admin-guide/mm/damon/usage.rst | 37 ++++++++++++++++---- 1 file changed, 30 insertions(+), 7 deletions(-) diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/a= dmin-guide/mm/damon/usage.rst index 282062b6f134..6272cd36590a 100644 --- a/Documentation/admin-guide/mm/damon/usage.rst +++ b/Documentation/admin-guide/mm/damon/usage.rst @@ -496,15 +496,24 @@ the files as above. Above is only for an example. =20 .. _tracepoint: =20 -Tracepoint for Monitoring Results -=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D +Tracepoints for Monitoring Results +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =20 Users can get the monitoring results via the :ref:`tried_regions -` or a tracepoint, ``damon:damon_aggregated``. -While the tried regions directory is useful for getting a snapshot, the -tracepoint is useful for getting a full record of the results. While the -monitoring is turned on, you could record the tracepoint events and show -results using tracepoint supporting tools like ``perf``. For example:: +`. The interface is useful for getting a +snapshot, but it could be inefficient for fully recording all the monitori= ng +results. For the purpose, two trace points, namely ``damon:damon_aggregat= ed`` +and ``damon:damos_before_apply``, are provided. ``damon:damon_aggregated`` +provides the whole monitoring results, while ``damon:damos_before_apply`` +provides the monitoring results for regions that each DAMON-based Operation +Scheme (:ref:`DAMOS `) is gonna be applied. Hence, +``damon:damos_before_apply`` is more useful for recording internal behavio= r of +DAMOS, or DAMOS target access +:ref:`pattern ` based query-like effici= ent +monitoring results recording. + +While the monitoring is turned on, you could record the tracepoint events = and +show results using tracepoint supporting tools like ``perf``. For example= :: =20 # echo on > monitor_on # perf record -e damon:damon_aggregated & @@ -527,6 +536,20 @@ counter). Finally the tenth field (``X``) shows the `= `age`` of the region (refer to :ref:`design ` for more details of the counter). =20 +If the event was ``damon:damos_beofre_apply``, the ``perf script`` output = would +be somewhat like below:: + + kdamond.0 47293 [000] 80801.060214: damon:damos_before_apply: ctx_idx= =3D0 scheme_idx=3D0 target_idx=3D0 nr_regions=3D11 121932607488-13512871116= 8: 0 136 + [...] + +Each line of the output represents each monitoring region that each DAMON-= based +Operation Scheme was about to be applied at the traced time. The first fi= ve +fields are as usual. It shows the index of the DAMON context (``ctx_idx= =3DX``) +of the scheme in the list of the contexts of the context's kdamond, the in= dex +of the scheme (``scheme_idx=3DX``) in the list of the schemes of the conte= xt, in +addition to the output of ``damon_aggregated`` tracepoint. + + .. _debugfs_interface: =20 debugfs Interface (DEPRECATED!) --=20 2.25.1