From nobody Tue Nov 30 21:35:18 2021 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 42E2818B26D9; Tue, 30 Nov 2021 21:35:31 +0000 (UTC) (envelope-from kevans@freebsd.org) Received: from smtp.freebsd.org (smtp.freebsd.org [IPv6:2610:1c1:1:606c::24b:4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "smtp.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4J3b9Z6fwfz3h8p; Tue, 30 Nov 2021 21:35:30 +0000 (UTC) (envelope-from kevans@freebsd.org) Received: from mail-qk1-f178.google.com (mail-qk1-f178.google.com [209.85.222.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "GTS CA 1D4" (verified OK)) (Authenticated sender: kevans) by smtp.freebsd.org (Postfix) with ESMTPSA id BEAD793ED; Tue, 30 Nov 2021 21:35:30 +0000 (UTC) (envelope-from kevans@freebsd.org) Received: by mail-qk1-f178.google.com with SMTP id de30so28541755qkb.0; Tue, 30 Nov 2021 13:35:30 -0800 (PST) X-Gm-Message-State: AOAM533GPoOgZdlccIQeh6RJA7oAr77FucJZZFQY85YJyalr12byAipV mIxkD4uiRcMHWTxzHx7DCxBMvtSFkNqKEV2BbiM= X-Google-Smtp-Source: ABdhPJxCfFGTNUuKfOm+pApaABKH6jHelwfwAjqKiZiqM7mmSxe8K3aXSEreaxQ04W5Z0Q43naV8/rwitFUjlerS4yA= X-Received: by 2002:a37:b944:: with SMTP id j65mr2141046qkf.708.1638308130154; Tue, 30 Nov 2021 13:35:30 -0800 (PST) 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 References: <202111301334.1AUDYJEU014078@gitrepo.freebsd.org> <69d4804d-1d94-7757-5c93-0d062f9c31c0@FreeBSD.org> In-Reply-To: <69d4804d-1d94-7757-5c93-0d062f9c31c0@FreeBSD.org> From: Kyle Evans Date: Tue, 30 Nov 2021 15:35:18 -0600 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: git: 3d9d64aa1846 - main - kern_tc: unify timecounter to bintime delta conversion To: Andriy Gapon Cc: src-committers , "" , dev-commits-src-main@freebsd.org Content-Type: text/plain; charset="UTF-8" ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1638308131; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=EoxAoeAxKwC2t61ujl5hC4/jw8GONvAweFPSZzPGfWQ=; b=IFbTHdiUQ27E1nkjLNUc+FbKAlLA0m38FF7KAkIpQimTEkTW6+48ZG+dis3nBUL7CXf+Ne 3iMxfNkze2mmcCW2jayosx9zIOl96u6Y5g4Ldq2SZ8czzpawnXBOePIU6FT0gTofaMsj/4 w7Uv7/cAct7Y4NB0HuvScvWiArnMFf0pKpUoUZDiEldp76zHisDjfnYkAInQyhSbZ2a6Ag 4MWChjmitYfe+YSIhp6cSu6SJFR0IjO2df47G6PdCV7GtdxVdrpC6yp6VQ0TJ0SU5ZR6xI AvfHnuY6Uy6WEyd77se7hJ5q/yK/s+Y7pFMeyTWnTp4oGLUa/DTLsmyrxci+Ww== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1638308131; a=rsa-sha256; cv=none; b=jvg3AKfIAS60S2n5uvQyl4bkGyRFQy1zLBVvigA0fCeDhzHuQr9eIzNRqGP26PDl6k8rbs IIrUEPLt0zwkRL8xrus8WI2dSaNpB0LeLw9tQ3LwOFrXExBOwt+2BIqOUzbYBFZ9grWQsR 1GxVzu8/ChYQz90HmAXQSVKXQ9CXDqsNBO0HOLd4YVTJsgjiENPaSM76JfeNpTKZ09qDzZ vpxDt9Ih6kwhW02wfEb5tgeKWYUlQfc9KEiXNQFR5oWq+AN5Is1+PQQL5BEfqYmjIrq9On 8O55xsgPU9wdcfsdx0U0i5axV3/Fu9fS36beqkPXK9fp/3FU9aPYv6VEuvpC0Q== ARC-Authentication-Results: i=1; mx1.freebsd.org; none X-ThisMailContainsUnwantedMimeParts: N On Tue, Nov 30, 2021 at 11:08 AM Andriy Gapon wrote: > > On 30/11/2021 18:14, Kyle Evans wrote: > > I wonder if this helps explain the behavior we saw when enabling TSC > > on VirtualBox guests. Threads doing small ~1 second or less sleeps > > would start to miss their wakeups, so we'd consistently see, e.g., > > shutdown issues after applying a high loading while we're waiting for > > bufdaemon threads. > > It very well may be the case. > The reason I arrived at this change is that we also sometimes saw the same > problem but on VMWware. That prompted me to add some diagnostic code to > sleepqueue to turn those missed wakeups into panics. > > As kib pointed out, mav recently made a change that would mask the problem as a > side effect: > https://cgit.FreeBSD.org/src/commit/?id=6df1359e5542f69179c142be1ea099d447e273d1 > But I wanted to fix the root cause anyway. > Ok, cool, thanks! I'll do some re-testing under VirtualBox and see if we can just revert this entirely: https://cgit.freebsd.org/src/commit/sys/x86/x86/tsc.c?id=8cc15b0dfc2f3299 Thanks, Kyle Evans