From owner-dev-commits-src-main@freebsd.org Wed Sep 8 18:11:09 2021 Return-Path: Delivered-To: dev-commits-src-main@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 1CCA367F3A3 for ; Wed, 8 Sep 2021 18:11:09 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: from mail-vs1-xe33.google.com (mail-vs1-xe33.google.com [IPv6:2607:f8b0:4864:20::e33]) (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 1O1" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4H4VZ46RZKz3C1S for ; Wed, 8 Sep 2021 18:11:08 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: by mail-vs1-xe33.google.com with SMTP id p14so2845155vsm.2 for ; Wed, 08 Sep 2021 11:11:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bsdimp-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=JjBmv9cHs56Jei8qQcF3UXx+A/bG+VGL7URpog8vZxk=; b=HJrLOCYGe/qrMGnXRf52nKNpjIIxow3W5CFIroQkggnQCnakj+fQukcMx9HN3dN30H CNcKORklI1CqBCjJAqLZmh8ZVkNNqj4iNqNH5qy8vVc38M9slmZ4H7KDyuWKo1SGIAnH ZwahJY1f3bms9r5DpH5TlOAYbjeHiW+xeRD+VGy7kItoCH7GTk7MDTQtpoe/AP6SNKCa XE+7QyYmmvlhHFSiPg8Wf7rTLHWuiErciwPpbEP+E3zBu/ug4UkCYyESJ6TGji4ikuIq YYS8EMmwXQbfZIprYSvnOHswUVdX6lNJkgbuBAU/XRI2+OrJPHW7ky1SnmOCCDVfIa0Z uJMA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=JjBmv9cHs56Jei8qQcF3UXx+A/bG+VGL7URpog8vZxk=; b=cYJQetFHudw03n1aTgx180v93QW0t1ZpSE61dFba4ZHO401QxR6FTtjm2h75kkvdmO oXt4rXbDh8hbII1qRYjfcVMSsw84qRovxJjntGD9OeA1jauCK982pD3eM+r/qgr4YbaL XipBHCLeifoi/qnGQUYBmpviYlnQAxjwUS++RPloeSkPPUzQ2y89w0Fp2pEJ6kynxhtd wpbpcI9+/CZXvh8lRRbPbZoEw2adijnQwCBDyjZu3vJKyBMXY2tmsCL21eZAngSdECuO EvprG0pIHejmdVHsnW0tAMQino59d8ETyKRJnzThvlM2KtXrf8nlAYl1RJBR5nNpkcuH 8ysw== X-Gm-Message-State: AOAM533t/026hMrZ4aj54bYVogGZvxrzmH6yk3aWcDgdLRmcOM3fioOy zGSdLq90dXbXJYdue8lQBWOWyCQB8zHwPg3aP7uTcg== X-Google-Smtp-Source: ABdhPJz9y6GGaDyRJ2HZ5YINgiYNKSpKouWLqs7vCjzsFLtclPuSI1NfhBH7OPEkVRHXagwew4c5frO9DDUPHdHFwxc= X-Received: by 2002:a67:1985:: with SMTP id 127mr3421717vsz.44.1631124668262; Wed, 08 Sep 2021 11:11:08 -0700 (PDT) MIME-Version: 1.0 References: <202109080132.1881WXPv069848@gitrepo.freebsd.org> <4b7bf983-8333-f4bc-6ce8-a59ac2fc7380@freebsd.org> In-Reply-To: <4b7bf983-8333-f4bc-6ce8-a59ac2fc7380@freebsd.org> From: Warner Losh Date: Wed, 8 Sep 2021 12:10:56 -0600 Message-ID: Subject: Re: git: a8b89dff6ac0 - main - Disable acpi_timer_test by default To: Colin Percival Cc: John Baldwin , src-committers , "" , dev-commits-src-main@freebsd.org X-Rspamd-Queue-Id: 4H4VZ46RZKz3C1S X-Spamd-Bar: ---- Authentication-Results: mx1.freebsd.org; none X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[] Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.34 X-BeenThere: dev-commits-src-main@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commit messages for the main branch of the src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 08 Sep 2021 18:11:09 -0000 On Wed, Sep 8, 2021, 11:47 AM Colin Percival wrote: > On 9/8/21 9:01 AM, John Baldwin wrote: > > On 9/7/21 6:32 PM, Colin Percival wrote: > >> Disable acpi_timer_test by default > >> This disables testing the ACPI timer by default, forcing the > use of > >> ACPI-fast rather than ACPI-safe. The broken-ACPI-timers workaround > >> can be re-enabled by setting the hw.acpi.timer_test_enabled=1 > tunable. > >> This speeds up the FreeBSD boot process by 140 ms on an EC2 > c5.xlarge > >> instance. > >> This change will not be MFCed. > >> Assuming no problems are reported, acpi_timer_test, the > associated > >> tunable, and the ACPI-safe timecounter should be removed in > FreeBSD 15. > >> Relnotes: The ACPI-safe timer is disabled in favour of > >> ACPI-fast; > >> if timekeeping issues are observed, please test > with > >> hw.acpi.timer_test_enabled=1 in loader.conf and > report > >> if that fixes the problem. > > > > Perhaps it should default to '1' for i386 and '0' otherwise? The > relevant > > chipsets were 32-bit only, so this would be a simple way to skip the > test for > > modern hardware, and you could probably MFC that safely. > > That option was discussed, but I decided that it was probably safer to > keep it enabled by default in 13 in case the test was detecting systems > which are broken in other ways. > > Googling for "ACPI-safe" (which shows up if the test fails) finds forum > discussions from the mid-2010s, but it's not clear whether that's due to > very old hardware, new ACPI timer issues, or other timekeeping problems > -- I figured it was best to play it safe for something which would be > going into a stable branch though. > I think John's suggestion is a good balance. It will also tell us if there is a need on amd64. Having it tagged as i386 also will highlight it better should the time come to remove it later. Warner -- > Colin Percival > Security Officer Emeritus, FreeBSD | The power to serve > Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid >