From nobody Mon Aug 28 20:33:48 2023 X-Original-To: current@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 4RZMj51TGbz4rwR9 for ; Mon, 28 Aug 2023 20:34:01 +0000 (UTC) (envelope-from Alexander@Leidinger.net) Received: from mailgate.Leidinger.net (bastille.leidinger.net [89.238.82.207]) (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 ECDSA (P-256) client-digest SHA256) (Client CN "mailgate.leidinger.net", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4RZMj36Th2z4HTq for ; Mon, 28 Aug 2023 20:33:59 +0000 (UTC) (envelope-from Alexander@Leidinger.net) Authentication-Results: mx1.freebsd.org; dkim=pass header.d=leidinger.net header.s=outgoing-alex header.b=sMXWX2ES; spf=pass (mx1.freebsd.org: domain of Alexander@Leidinger.net designates 89.238.82.207 as permitted sender) smtp.mailfrom=Alexander@Leidinger.net; dmarc=pass (policy=quarantine) header.from=leidinger.net Received: from webmail2.leidinger.net (roundcube.Leidinger.net [192.168.1.123]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (Client did not present a certificate) (Authenticated sender: Alexander@Leidinger.net) by outgoing.leidinger.net (Postfix) with ESMTPSA id 7229B504; Mon, 28 Aug 2023 22:33:48 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=leidinger.net; s=outgoing-alex; t=1693254833; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=33B06ZO80UcFiUIyahPMCtj5xKCZDGA7UkFc3icJIzA=; b=sMXWX2ESsbBOCgAh6c3J4GxsDvTsIojeAjmhwmfJ3zVdLN+i64NcLl7FlfOdT7S0NOiyaZ 5Vd3R593SwdukNKFyetDrgsJ+LHyUhF2MTNHVB/C7Ly5JWclly2qVuwgzLNea+Prb0mJKk sRfF91YRy0OA8rESqd71nSwhGxA1wT5+Ommez7PwqRAUG4AVBMBBwHRDK/vRnxBZoI93xe /tpOZd4QsNnjpwIUjJ58tyz4FLLGuAlYHL6C9g8mI2jpdq5OQ/wz5M/dfeDjS6QkBrFAqc gxYwsxkMWEMOlHq0qjRmGPw0BPAotwpXeIhJPGWadY83HMvDaMF6v47kc1FUVQ== List-Id: Discussions about the use of FreeBSD-current List-Archive: https://lists.freebsd.org/archives/freebsd-current List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-current@freebsd.org MIME-Version: 1.0 Date: Mon, 28 Aug 2023 22:33:48 +0200 From: Alexander Leidinger To: Mateusz Guzik Cc: Konstantin Belousov , current@freebsd.org Subject: Re: Speed improvements in ZFS In-Reply-To: References: <88e837aeb5a65c1f001de2077fb7bcbd@Leidinger.net> <4d60bd12b482e020fd4b186a9ec1a250@Leidinger.net> <73f7c9d3db8f117deb077fb17b1e352a@Leidinger.net> <58493b568dbe9fb52cc55de86e01f5e2@Leidinger.net> <58ac6211235c52d744666e8ae2ec7568@Leidinger.net> <444770b977b02b98985928bea450e4ce@Leidinger.net> Message-ID: <076f09cc0b99643072d8b80a6ec5b03b@Leidinger.net> X-Sender: Alexander@Leidinger.net Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit X-Spamd-Bar: --- X-Spamd-Result: default: False [-3.90 / 15.00]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; NEURAL_HAM_SHORT(-1.00)[-1.000]; DMARC_POLICY_ALLOW(-0.50)[leidinger.net,quarantine]; R_SPF_ALLOW(-0.20)[+mx]; R_DKIM_ALLOW(-0.20)[leidinger.net:s=outgoing-alex]; MIME_GOOD(-0.10)[text/plain]; ONCE_RECEIVED(0.10)[]; FREEMAIL_TO(0.00)[gmail.com]; RCVD_COUNT_ONE(0.00)[1]; ASN(0.00)[asn:34240, ipnet:89.238.64.0/18, country:DE]; MLMMJ_DEST(0.00)[current@freebsd.org]; MIME_TRACE(0.00)[0:+]; FREEMAIL_CC(0.00)[gmail.com,freebsd.org]; FROM_EQ_ENVFROM(0.00)[]; TO_MATCH_ENVRCPT_SOME(0.00)[]; RCVD_TLS_ALL(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; ARC_NA(0.00)[]; DKIM_TRACE(0.00)[leidinger.net:+]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; RCPT_COUNT_THREE(0.00)[3]; RCVD_VIA_SMTP_AUTH(0.00)[] X-Rspamd-Queue-Id: 4RZMj36Th2z4HTq Am 2023-08-22 18:59, schrieb Mateusz Guzik: > On 8/22/23, Alexander Leidinger wrote: >> Am 2023-08-21 10:53, schrieb Konstantin Belousov: >>> On Mon, Aug 21, 2023 at 08:19:28AM +0200, Alexander Leidinger wrote: >>>> Am 2023-08-20 23:17, schrieb Konstantin Belousov: >>>> > On Sun, Aug 20, 2023 at 11:07:08PM +0200, Mateusz Guzik wrote: >>>> > > On 8/20/23, Alexander Leidinger wrote: >>>> > > > Am 2023-08-20 22:02, schrieb Mateusz Guzik: >>>> > > >> On 8/20/23, Alexander Leidinger wrote: >>>> > > >>> Am 2023-08-20 19:10, schrieb Mateusz Guzik: >>>> > > >>>> On 8/18/23, Alexander Leidinger >>>> > > >>>> wrote: >>>> > > >>> >>>> > > >>>>> I have a 51MB text file, compressed to about 1MB. Are you >>>> > > >>>>> interested >>>> > > >>>>> to >>>> > > >>>>> get it? >>>> > > >>>>> >>>> > > >>>> >>>> > > >>>> Your problem is not the vnode limit, but nullfs. >>>> > > >>>> >>>> > > >>>> https://people.freebsd.org/~mjg/netchild-periodic-find.svg >>>> > > >>> >>>> > > >>> 122 nullfs mounts on this system. And every jail I setup has >>>> > > >>> several >>>> > > >>> null mounts. One basesystem mounted into every jail, and then >>>> > > >>> shared >>>> > > >>> ports (packages/distfiles/ccache) across all of them. >>>> > > >>> >>>> > > >>>> First, some of the contention is notorious VI_LOCK in order to >>>> > > >>>> do >>>> > > >>>> anything. >>>> > > >>>> >>>> > > >>>> But more importantly the mind-boggling off-cpu time comes from >>>> > > >>>> exclusive locking which should not be there to begin with -- as >>>> > > >>>> in >>>> > > >>>> that xlock in stat should be a slock. >>>> > > >>>> >>>> > > >>>> Maybe I'm going to look into it later. >>>> > > >>> >>>> > > >>> That would be fantastic. >>>> > > >>> >>>> > > >> >>>> > > >> I did a quick test, things are shared locked as expected. >>>> > > >> >>>> > > >> However, I found the following: >>>> > > >> if ((xmp->nullm_flags & NULLM_CACHE) != 0) { >>>> > > >> mp->mnt_kern_flag |= >>>> > > >> lowerrootvp->v_mount->mnt_kern_flag & >>>> > > >> (MNTK_SHARED_WRITES | MNTK_LOOKUP_SHARED | >>>> > > >> MNTK_EXTENDED_SHARED); >>>> > > >> } >>>> > > >> >>>> > > >> are you using the "nocache" option? it has a side effect of >>>> > > >> xlocking >>>> > > > >>>> > > > I use noatime, noexec, nosuid, nfsv4acls. I do NOT use nocache. >>>> > > > >>>> > > >>>> > > If you don't have "nocache" on null mounts, then I don't see how >>>> > > this >>>> > > could happen. >>>> > >>>> > There is also MNTK_NULL_NOCACHE on lower fs, which is currently set >>>> > for >>>> > fuse and nfs at least. >>>> >>>> 11 of those 122 nullfs mounts are ZFS datasets which are also NFS >>>> exported. >>>> 6 of those nullfs mounts are also exported via Samba. The NFS >>>> exports >>>> shouldn't be needed anymore, I will remove them. >>> By nfs I meant nfs client, not nfs exports. >> >> No NFS client mounts anywhere on this system. So where is this >> exclusive >> lock coming from then... >> This is a ZFS system. 2 pools: one for the root, one for anything I >> need >> space for. Both pools reside on the same disks. The root pool is a >> 3-way >> mirror, the "space-pool" is a 5-disk raidz2. All jails are on the >> space-pool. The jails are all basejail-style jails. >> > > While I don't see why xlocking happens, you should be able to dtrace > or printf your way into finding out. dtrace looks to me like a faster approach to get to the root than printf... my first naive try is to detect exclusive locks. I'm not 100% sure I got it right, but at least dtrace doesn't complain about it: ---snip--- #pragma D option dynvarsize=32m fbt:nullfs:null_lock:entry /args[0]->a_flags & 0x080000 != 0/ { stack(); } ---snip--- In which direction should I look with dtrace if this works in tonights run of periodic? I don't have enough knowledge about VFS to come up with some immediate ideas. Bye, Alexander. -- http://www.Leidinger.net Alexander@Leidinger.net: PGP 0x8F31830F9F2772BF http://www.FreeBSD.org netchild@FreeBSD.org : PGP 0x8F31830F9F2772BF