From patchwork Mon Sep 13 13:13:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Venky Shankar X-Patchwork-Id: 510996 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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham 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 85997C433F5 for ; Mon, 13 Sep 2021 13:13:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 621EC60FA0 for ; Mon, 13 Sep 2021 13:13:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236675AbhIMNOx (ORCPT ); Mon, 13 Sep 2021 09:14:53 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:29579 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240439AbhIMNOk (ORCPT ); Mon, 13 Sep 2021 09:14:40 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1631538802; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=hWmcRpWnOsp+N9j6fGp+ij04uAX9QRgGPLAr7qd6RP4=; b=dn0e1hKYMFjNGZHhaVnlfobSdX6DyauRGOLCblz+7GOnXajfiMLxajU9gIg8Cis7MLm2fn eMGrjfO0GArR2Wwd4KgJle6Q2Bww9wCDBRSx1gBKMkNGlFhn5ZgkBGqihLS/ELC6kTrKkR lny+tExeEPx4o3mQJqinifoR1bD2W4o= Received: from mail-pg1-f198.google.com (mail-pg1-f198.google.com [209.85.215.198]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-5-gxcIx9uWPEqe1qyyKp9iBA-1; Mon, 13 Sep 2021 09:13:21 -0400 X-MC-Unique: gxcIx9uWPEqe1qyyKp9iBA-1 Received: by mail-pg1-f198.google.com with SMTP id d5-20020a63ed05000000b002688d3aff8aso7361655pgi.2 for ; Mon, 13 Sep 2021 06:13:21 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=hWmcRpWnOsp+N9j6fGp+ij04uAX9QRgGPLAr7qd6RP4=; b=lW8dS/AnUOUEDgzGaFH1fSXrBcFX66vs3MkoIFy5J1+a2Z2IiMQzo2HHqAOoCzirmW 70CZw20QyNtOC8xiwjXzkxT3cNNsv+UZrRCcWNtJJkBYEI9U/Z4z4s1gW6ndpy3lrnHA qHvXTTHUBPymGV0BxXgA+KwHqUvBcr140VYsk1Q2WCFtGyiJ5aK5BP7t8IMIDcOeQdVp +vCwV2JTBdXlti0s4mP2jy+bbJEOR580+rloTeJIGdjJORpVegAF6zyPynEVtuxoqOV9 L5Xm9pJyZe6RttByA2+ZpNyGwD2PM+AHAvwlwQHylvCdpOOYgyRkQl9+k0b+PI03CsNJ s0tA== X-Gm-Message-State: AOAM530X5nACVCJTlmt7cRctghOH8oz2P+vg1SgZthakZiP725sksKC+ Y/IoaMWn1GlZDKwVzOqYYHXGYPgN06XrCrGl9GJ2OmztlfrVgClLmtOWdoJiBNzBJLHK96HuYEz STkeaxD9oPjVhpzISEXEZGw== X-Received: by 2002:a17:90a:4d8d:: with SMTP id m13mr12917391pjh.190.1631538800253; Mon, 13 Sep 2021 06:13:20 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzFQMkfGNt+i/6BzKNKcQmAjxURStWyMr2yGywEz5WtCu7T62yU7+vMvqilnbGfvpUsIWG7Vw== X-Received: by 2002:a17:90a:4d8d:: with SMTP id m13mr12917370pjh.190.1631538800042; Mon, 13 Sep 2021 06:13:20 -0700 (PDT) Received: from h3ckers-pride.redhat.com ([49.207.198.118]) by smtp.gmail.com with ESMTPSA id i10sm7362010pfk.151.2021.09.13.06.13.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 13 Sep 2021 06:13:19 -0700 (PDT) From: Venky Shankar To: jlayton@redhat.com, pdonnell@redhat.com, xiubli@redhat.com Cc: ceph-devel@vger.kernel.org, Venky Shankar Subject: [PATCH v1 0/4] ceph: forward average read/write/metadata latency Date: Mon, 13 Sep 2021 18:43:07 +0530 Message-Id: <20210913131311.1347903-1-vshankar@redhat.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org Right now, cumulative read/write/metadata latencies are tracked and are periodically forwarded to the MDS. These meterics are not particularly useful. A much more useful metric is the average latency and standard deviation (stdev) which is what this series of patches aims to do. The userspace (libcephfs+tool) changes are here:: https://github.com/ceph/ceph/pull/41397 The math involved in keeping track of the average latency and stdev seems incorrect, so, this series fixes that up too (closely mimics how its done in userspace with some restrictions obviously) as per:: NEW_AVG = OLD_AVG + ((latency - OLD_AVG) / total_ops) NEW_STDEV = SQRT(((OLD_STDEV + (latency - OLD_AVG)*(latency - NEW_AVG)) / (total_ops - 1))) Note that the cumulative latencies are still forwarded to the MDS but the tool (cephfs-top) ignores it altogether. Venky Shankar (4): ceph: use "struct ceph_timespec" for r/w/m latencies ceph: track average/stdev r/w/m latency ceph: include average/stddev r/w/m latency in mds metrics ceph: use tracked average r/w/m latencies to display metrics in debugfs fs/ceph/debugfs.c | 12 +++---- fs/ceph/metric.c | 81 +++++++++++++++++++++++++---------------------- fs/ceph/metric.h | 64 +++++++++++++++++++++++-------------- 3 files changed, 90 insertions(+), 67 deletions(-)