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=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 76229C432C2 for ; Wed, 25 Sep 2019 23:03:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4DDD920640 for ; Wed, 25 Sep 2019 23:03:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569452622; bh=30m8Bj/9Yrhu6rdft1hnYF9b79GkkQHGW8a4CX47k+Q=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=zDoluOGVfGT35JyItCloQfbmgSeHkLZf1UK4K+Za3Q17DNIy8/956FPPInnfqGO8i 0/i7r+OTAgxOTHuBxzuq96Wma9uCcnVm0fNEy+XJLedmnqIMLnd8IX8Kn9Idv8Ovuj +kXJCG4r97SBH5+ceCv+ZwcKAmc62jKzVFzl7JLA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730614AbfIYXDi (ORCPT ); Wed, 25 Sep 2019 19:03:38 -0400 Received: from mail-qt1-f195.google.com ([209.85.160.195]:39666 "EHLO mail-qt1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726206AbfIYXDi (ORCPT ); Wed, 25 Sep 2019 19:03:38 -0400 Received: by mail-qt1-f195.google.com with SMTP id n7so535466qtb.6; Wed, 25 Sep 2019 16:03:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=WfbXh+sodiUMPQSO5yCeqiJJDmHL2yMhTTI21O9c//4=; b=UrO+9FhI4EIs4jI4yXfKf1L+DbuNMlCxcVZ3jN5cwJ77HfdAjqNgQ6FQPxLj6MbdI5 EQ/qM8/S1CQq7aJbPc4BEHeXaKa0t8kWWT5CI/Ss8KJpfdfe8ErjJVNEUNWUDkWlTdu7 CHchGLYEiaLnnldmMtFmLQKgaZqfp6lWYUGq4/CRCyN96qPXjBLljijuJ4/6rOpNNE/B P/9roPgUV+Yc+bU/97dcTbYlgJnckw5Lls8VQSeJnLllwEXdKFmD+ONt+yzarNqHB0kZ WhlCKuVX9JQyMt2nUCrCRDD5K/0JcLluu+G+Yq3HIEN3rNKrvMOGWYzCiyxaKhpZuEsy Of9w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=WfbXh+sodiUMPQSO5yCeqiJJDmHL2yMhTTI21O9c//4=; b=ekAeYulb6w4JboYVzWkX/GBojQ73c5G1/mDiGRmwFxIdmx4zZ+s9vktB59bfSQPSfK ue/0atMEHabcS8kUt0dlRJBB6V2ZMjNMiln0vxCqv8wxE2foJmMhFjTsHojV6EhKwLeU IFvzLS0BX9S1HvKxSjy29yKODkZhuaN6lUx7Gv8riU8lbEeQCn8RjPXAlxm7MhCTth0K CiUZRY8iEsmi8rZmWgJ/1KjX93uhW+k8uj0EWgLDuAuTtBa/mQOHtCZoVQcXyXOhI7rW QVitvmqzbdIoPnraESfM/H7v5uq3M7tRVrKrGAvsnDtKb0KrU+/WrSNRyzCiPCrenMnt nZqw== X-Gm-Message-State: APjAAAWg4QhdiWFSaEkCwx5xefZdpcDDdEBaEaSg7+BfTjmoO94Ndi6C 0HT8K9LqdV+AAJWmCMh2vnw= X-Google-Smtp-Source: APXvYqyC1FyjGChJ2Qd1VW5+w/5vvUgYmAgGVElejt3WCWCezoA05O48V25SM3ipL5VdElk9+zyedw== X-Received: by 2002:ac8:100b:: with SMTP id z11mr953244qti.377.1569452617529; Wed, 25 Sep 2019 16:03:37 -0700 (PDT) Received: from localhost ([2620:10d:c091:500::3:a001]) by smtp.gmail.com with ESMTPSA id u43sm265769qte.19.2019.09.25.16.03.36 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 25 Sep 2019 16:03:37 -0700 (PDT) Date: Wed, 25 Sep 2019 16:03:35 -0700 From: Tejun Heo To: Jens Axboe Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, cgroups@vger.kernel.org Subject: [PATCH 3/3 for-5.4/block] iocost: bump up default latency targets for hard disks Message-ID: <20190925230335.GK2233839@devbig004.ftw2.facebook.com> References: <20190925230207.GI2233839@devbig004.ftw2.facebook.com> <20190925230309.GJ2233839@devbig004.ftw2.facebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190925230309.GJ2233839@devbig004.ftw2.facebook.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org The default hard disk param sets latency targets at 50ms. As the default target percentiles are zero, these don't directly regulate vrate; however, they're still used to calculate the period length - 100ms in this case. This is excessively low. A SATA drive with QD32 saturated with random IOs can easily reach avg completion latency of several hundred msecs. A period duration which is substantially lower than avg completion latency can lead to wildly fluctuating vrate. Let's bump up the default latency targets to 250ms so that the period duration is sufficiently long. Signed-off-by: Tejun Heo --- block/blk-iocost.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -529,8 +529,8 @@ struct iocg_wake_ctx { static const struct ioc_params autop[] = { [AUTOP_HDD] = { .qos = { - [QOS_RLAT] = 50000, /* 50ms */ - [QOS_WLAT] = 50000, + [QOS_RLAT] = 250000, /* 250ms */ + [QOS_WLAT] = 250000, [QOS_MIN] = VRATE_MIN_PPM, [QOS_MAX] = VRATE_MAX_PPM, },