From owner-freebsd-current@freebsd.org Wed Jan 27 20:03:04 2021 Return-Path: Delivered-To: freebsd-current@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 B9E6C4E82A9 for ; Wed, 27 Jan 2021 20:03:04 +0000 (UTC) (envelope-from yasu@utahime.org) Received: from maybe.home.utahime.org (gate.home.utahime.org [183.180.29.210]) (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 did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4DQvfb4QKHz3JFt for ; Wed, 27 Jan 2021 20:03:03 +0000 (UTC) (envelope-from yasu@utahime.org) Received: from eastasia.home.utahime.org (eastasia.home.utahime.org [192.168.174.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384) server-digest SHA384) (No client certificate requested) by maybe.home.utahime.org (Postfix) with ESMTPS id CB62F1284C for ; Thu, 28 Jan 2021 05:02:59 +0900 (JST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=utahime.org; s=maybe2019112701; t=1611777779; bh=NE4mKrN+P/4VEEgEEaK7FywDpUe+9n3zjY2epagpaMc=; h=Date:To:Subject:From:In-Reply-To:References; b=SygIwddrt2BBqi++vIhcojiLBJHWAe7vIyBhzWYMhGHCv2vFXotROAx41ucbFPrTM NlngoQ4cM/S78bpzYQMynh2gyCglb0wHCQk1iHLdni4gLWZhB+T+3eGBzdqJ7TEgp6 iQzb6xosdP6z1pFpZUyV1JT7aC2OOlHppubfmmAlYhr+rbFvHldaTUvXHwHA3CrPFN Ub7rc2qrCUxcO+6ion/FalTR6o4x/Tdj1GVn1vmxszwjTWR/FMKeM0RvXGsi49Jpsg 4eL10jQed6Ep8ZpP8fxqgGvSa+wrsndBK+dKyrgs/3sz6Ns3CBL9oAx3sfPOgqmG5r xagRhKVjdlr+g== Received: from localhost (rolling.home.utahime.org [192.168.174.11]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384) server-digest SHA384) (No client certificate requested) by eastasia.home.utahime.org (Postfix) with ESMTPSA id D32F91C30E; Thu, 28 Jan 2021 05:02:58 +0900 (JST) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.0 at eastasia.home.utahime.org Date: Thu, 28 Jan 2021 05:02:42 +0900 (JST) Message-Id: <20210128.050242.1986722766748729591.yasu@utahime.org> To: freebsd-current@freebsd.org Subject: Re: Waiting for bufdaemon From: Yasuhiro Kimura In-Reply-To: <20210116.040323.136067379540977557.yasu@utahime.org> References: <7c4da243-52ff-c5ee-3d56-1ae651286e0e@alvermark.net> <20210115.201030.1395690536446474720.yasu@utahime.org> <20210116.040323.136067379540977557.yasu@utahime.org> X-Mailer: Mew version 6.8 on Emacs 27.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 4DQvfb4QKHz3JFt X-Spamd-Bar: / Authentication-Results: mx1.freebsd.org; dkim=pass header.d=utahime.org header.s=maybe2019112701 header.b=SygIwddr; dmarc=none; spf=pass (mx1.freebsd.org: domain of yasu@utahime.org designates 183.180.29.210 as permitted sender) smtp.mailfrom=yasu@utahime.org X-Spamd-Result: default: False [-0.70 / 15.00]; RCVD_VIA_SMTP_AUTH(0.00)[]; MV_CASE(0.50)[]; R_SPF_ALLOW(-0.20)[+a:spf-authorized.utahime.org]; TO_DN_NONE(0.00)[]; HFILTER_HELO_IP_A(1.00)[maybe.home.utahime.org]; HFILTER_HELO_NORES_A_OR_MX(0.30)[maybe.home.utahime.org]; RCVD_COUNT_THREE(0.00)[3]; DKIM_TRACE(0.00)[utahime.org:+]; NEURAL_HAM_SHORT(-1.00)[-0.997]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; RBL_DBL_DONT_QUERY_IPS(0.00)[183.180.29.210:from]; ASN(0.00)[asn:2519, ipnet:183.180.0.0/16, country:JP]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; R_DKIM_ALLOW(-0.20)[utahime.org:s=maybe2019112701]; FROM_HAS_DN(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; MIME_GOOD(-0.10)[text/plain]; DMARC_NA(0.00)[utahime.org]; PREVIOUSLY_DELIVERED(0.00)[freebsd-current@freebsd.org]; RCPT_COUNT_ONE(0.00)[1]; SPAMHAUS_ZRD(0.00)[183.180.29.210:from:127.0.2.255]; MID_CONTAINS_FROM(1.00)[]; RCVD_TLS_ALL(0.00)[]; MAILMAN_DEST(0.00)[freebsd-current] X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 27 Jan 2021 20:03:04 -0000 From: Yasuhiro Kimura Subject: Re: Waiting for bufdaemon Date: Sat, 16 Jan 2021 04:03:23 +0900 (JST) > From: Yasuhiro Kimura > Subject: Re: Waiting for bufdaemon > Date: Fri, 15 Jan 2021 20:10:30 +0900 (JST) > >> I have been experiencing same problem with my 13-CURRENT amd64 >> VirtualBox VM for about a month. The conditions that the problem >> happens are unclear and all what I can say is >> >> * It happens only after I login in the VM and do something for a >> while. If I boot the VM and shut it down immediately, it never >> happens. >> * When the problem happens, one or more unkillable processes seem to >> be left. > > CPU of my host is not AMD but Intel. According to the > /var/run/dmesg.boot of VM, information of CPU is as following. > > CPU: Intel(R) Core(TM) i7-9700 CPU @ 3.00GHz (3000.09-MHz K8-class CPU) > Origin="GenuineIntel" Id=0x906ed Family=0x6 Model=0x9e Stepping=13 > Features=0x1783fbff > Features2=0x5eda2203 > AMD Features=0x28100800 > AMD Features2=0x121 > Structured Extended Features=0x842421 > Structured Extended Features3=0x30000400 > IA32_ARCH_CAPS=0x29 > TSC: P-state invariant > > Just FYI. It took for a while to investigate, but according to the result of bisect following commit is the source of problem in my case. ---------------------------------------------------------------------- commit 84eaf2ccc6a Author: Konstantin Belousov Date: Mon Dec 21 19:02:31 2020 +0200 x86: stop punishing VMs with low priority for TSC timecounter I suspect that virtualization techniques improved from the time when we have to effectively disable TSC use in VM. For instance, it was reported (complained) in https://github.com/JuliaLang/julia/issues/38877 that FreeBSD is groundlessly slow on AWS with some loads. Remove the check and start watching for complaints. Reviewed by: emaste, grehan Discussed with: cperciva Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D27629 ---------------------------------------------------------------------- I confirmed the problem still happens with 5c325977b11 but reverting above commit fixes it. --- Yasuhiro Kimura