From owner-freebsd-current@freebsd.org Fri Oct 30 22:47:41 2020 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 894E645D684 for ; Fri, 30 Oct 2020 22:47:41 +0000 (UTC) (envelope-from slw@zxy.spb.ru) Received: from zxy.spb.ru (zxy.spb.ru [195.70.199.98]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4CNHWc1jqQz4ZFX for ; Fri, 30 Oct 2020 22:47:40 +0000 (UTC) (envelope-from slw@zxy.spb.ru) Received: from slw by zxy.spb.ru with local (Exim 4.86 (FreeBSD)) (envelope-from ) id 1kYdBH-000KPa-2u; Sat, 31 Oct 2020 01:47:35 +0300 Date: Sat, 31 Oct 2020 01:47:35 +0300 From: Slawa Olhovchenkov To: Cy Schubert Cc: qroxana , freebsd-current@freebsd.org Subject: Re: OpenZFS: kldload zfs.ko freezes on i386 4GB memory Message-ID: <20201030224734.GH2033@zxy.spb.ru> References: <202010300313.09U3D0KZ006216@slippy.cwsent.com> <20201030204622.GF2033@zxy.spb.ru> <202010302053.09UKrAXc031272@slippy.cwsent.com> <20201030220809.GG2033@zxy.spb.ru> <202010302234.09UMYA5d032018@slippy.cwsent.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202010302234.09UMYA5d032018@slippy.cwsent.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: slw@zxy.spb.ru X-SA-Exim-Scanned: No (on zxy.spb.ru); SAEximRunCond expanded to false X-Rspamd-Queue-Id: 4CNHWc1jqQz4ZFX X-Spamd-Bar: / X-Spamd-Result: default: False [-0.61 / 15.00]; RCVD_TLS_LAST(0.00)[]; ARC_NA(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[3]; TO_DN_SOME(0.00)[]; NEURAL_HAM_LONG(-0.96)[-0.956]; MIME_GOOD(-0.10)[text/plain]; DMARC_NA(0.00)[zxy.spb.ru]; AUTH_NA(1.00)[]; NEURAL_SPAM_SHORT(0.30)[0.298]; TO_MATCH_ENVRCPT_SOME(0.00)[]; NEURAL_HAM_MEDIUM(-0.86)[-0.856]; R_SPF_NA(0.00)[no SPF record]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:5495, ipnet:195.70.192.0/19, country:RU]; FREEMAIL_CC(0.00)[mail.ru,freebsd.org]; MAILMAN_DEST(0.00)[freebsd-current]; RCVD_COUNT_TWO(0.00)[2] X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.33 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: Fri, 30 Oct 2020 22:47:41 -0000 On Fri, Oct 30, 2020 at 03:34:10PM -0700, Cy Schubert wrote: > In message <20201030220809.GG2033@zxy.spb.ru>, Slawa Olhovchenkov writes: > > On Fri, Oct 30, 2020 at 01:53:10PM -0700, Cy Schubert wrote: > > > > > In message <20201030204622.GF2033@zxy.spb.ru>, Slawa Olhovchenkov writes: > > > > On Thu, Oct 29, 2020 at 08:13:00PM -0700, Cy Schubert wrote: > > > > > > > > > In message , qroxan > > a > > > > > writes > > > > > : > > > > > > > > > > > > Hi, > > > > > > > > > > > > I have an old i386 machine running r364479. After upgrading to > > > > > > r367045, running kldload zfs.ko freezes the whole system. > > > > > > > > > > > > I also tried to replace the 4GB memory with another 2GB one > > > > > > and kldload zfs.ko works without freezing the machine. > > > > > > > > > > ZFS ARC stresses memory. I've found a number of bad RAM chips over the > > > > > years using ZFS. > > > > > > > > > > The OpenZFS upgrade significantly changed how it manages ARC. It's like > > ly > > > > > that prior to the OpenZFS upgrade your memory wasn't stressed to the po > > int > > > > > of failure. You can try to mask the problem by reducing your RAM clock > > rate > > > > > > > > > or or increase one of the other latency settings in your BIOS. However, > > > > > > > again, this only masks an already weak RAM chip. > > > > > > > > Sounds like performance drop and regression > > > > > > How so. Please explain. > > > > More stresses memory usually refers to performance penalty. > > Usually way for better performance is reduce memory access. > > The reason filesystems (UFS, ZFS, EXT4, etc.) cache is to avoid disk > accesses. Nanoseconds vs milliseconds. I mean compared ZoL ZFS ARC vs old (BSD/Opensolaris/Illumos) ZFS ARC. Any reaason to rise ARC hit rate in ZoL case?