From nobody Mon Jan 10 02:43:30 2022 X-Original-To: dev-commits-src-main@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 0E3C0194B4E3; Mon, 10 Jan 2022 02:43:38 +0000 (UTC) (envelope-from mavbsd@gmail.com) Received: from mail-qv1-xf2e.google.com (mail-qv1-xf2e.google.com [IPv6:2607:f8b0:4864:20::f2e]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1D4" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4JXJ6d6n8Mz3jXb; Mon, 10 Jan 2022 02:43:37 +0000 (UTC) (envelope-from mavbsd@gmail.com) Received: by mail-qv1-xf2e.google.com with SMTP id jr5so2077264qvb.11; Sun, 09 Jan 2022 18:43:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=Ujz1a639nS2n+YNMWVTUQ90a9/WUtUxcs3fRqDQ27PE=; b=ckYFS9S1137iHq5mXQZBsY1QLCMBH2DkIc6CvBvFWiYBTSuhVUE1jqqzi95PkNaYq9 TV6Bek/rDs02c/rZq9tl7CX9TMdQe5kp/3KXxnxaSHd27EPWgQvDcVMsASQUNQcAzT7F kTJPdlo2IiN41gTGMAbuM4fFarvRqG1Agl7j8AfLywmEIp8RSaEmtVzCkqMH21qjG6y9 3pWrgFzqnx+0K2eRZu3vcs4INuep4s54eR+/Ncxsfa4x6VHywTWNsYh9AKGagrbwc4PB llCCepLckxcpr81GxOLfYXOcli3Wmjc4uGyLGOqW7yN/4/V9iMtzzz0zsF7uBiebdwMk HTnQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:subject:to:cc:references:from:message-id :date:user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=Ujz1a639nS2n+YNMWVTUQ90a9/WUtUxcs3fRqDQ27PE=; b=Ysl0dUcZtHH9to9Oqk00GLydruBDcYDFeTKqq8X9EMfZQ+NozdYjWXi5HchjdOxaLH VdFKzKUw7J7IO32/YCvNWcd+PZuAW5Gw9DAfXLr/0GVVxVVz10Zcr4oasRALTM4kNS9Y 4HQUG8rCC3Tkhtc+AtrWoaYSw9U9ZF1Gj8aeSHdz4fQZuKT6fj1iEz14Gxg5cO/t2sgt +F0lI/ZZf8tz6iwyvr0TxSmdB5g5pMSfaIvzPz3L4QU0rS0Ptnpl+ghq2tdlngCPjPR1 idCtH7VPdvAlHCa7rhuX8ouv0sXME/rb+LBEulxeL6hSlDzYw1PO5y/mLckPx2H1Y9IG ZOmw== X-Gm-Message-State: AOAM532aar+ynBfXPk5zcck9ciCM3PWXrfu+QBENO/n9a+SEiLUGLRjw SyWgqC1N9cmk6oP+HcBybJbjE46+KPg= X-Google-Smtp-Source: ABdhPJw331yUyzmeWDODtldVJXFMLIDCCVy79D8qoT7+AVkPqoUl5kfOyv3wHTaslbGw/kOZnPIS0Q== X-Received: by 2002:ad4:5dc2:: with SMTP id m2mr1772127qvh.58.1641782611043; Sun, 09 Jan 2022 18:43:31 -0800 (PST) Received: from spectre.mavhome.dp.ua (104-55-12-234.lightspeed.knvltn.sbcglobal.net. [104.55.12.234]) by smtp.gmail.com with ESMTPSA id g22sm3892148qtk.23.2022.01.09.18.43.30 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 09 Jan 2022 18:43:30 -0800 (PST) Sender: Alexander Motin Subject: Re: git: cb1f5d11366d - main - Reduce minimum idle hardclock rate from 2Hz to 1Hz. To: Konstantin Belousov Cc: src-committers@freebsd.org, dev-commits-src-all@freebsd.org, dev-commits-src-main@freebsd.org References: <202201100026.20A0Q1fs045878@gitrepo.freebsd.org> From: Alexander Motin Message-ID: <18820cc0-8575-a678-84f6-5bca2c0b0498@FreeBSD.org> Date: Sun, 9 Jan 2022 21:43:30 -0500 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 List-Id: Commit messages for the main branch of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-main List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-dev-commits-src-main@freebsd.org X-BeenThere: dev-commits-src-main@freebsd.org MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 4JXJ6d6n8Mz3jXb X-Spamd-Bar: ---- Authentication-Results: mx1.freebsd.org; none X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[] X-ThisMailContainsUnwantedMimeParts: N On 09.01.2022 21:33, Konstantin Belousov wrote: > On Mon, Jan 10, 2022 at 12:26:01AM +0000, Alexander Motin wrote: >> The branch main has been updated by mav: >> >> URL: https://cgit.FreeBSD.org/src/commit/?id=cb1f5d11366dc9b803f2755d83fe02599830882a >> >> commit cb1f5d11366dc9b803f2755d83fe02599830882a >> Author: Alexander Motin >> AuthorDate: 2022-01-10 00:17:43 +0000 >> Commit: Alexander Motin >> CommitDate: 2022-01-10 00:25:56 +0000 >> >> Reduce minimum idle hardclock rate from 2Hz to 1Hz. >> >> On idle 80-thread system it allows to improve package-level idle state >> residency and so power consumption by several percent. > Are you sure that this is safe? > > Our timecounters are tailored to wrap at 1sec, at least the most precise/ > important TSC-low is. If idle system interrupts with 1Hz frequency, > it probably comes dangerously close to situations where tc_windup() could > be missed. That particular timecounters wrap around should be handled there long ago with tc_min_ticktock_freq. When needed it should increase hardclock on BSP (could be any other CPU, so why not BSP) up to the minimally safe rate. -- Alexander Motin