Date: Sun, 20 Aug 2023 22:13:43 +0200 From: Alexander Leidinger <Alexander@Leidinger.net> To: Mateusz Guzik <mjguzik@gmail.com> Cc: current@freebsd.org Subject: Re: Speed improvements in ZFS Message-ID: <58493b568dbe9fb52cc55de86e01f5e2@Leidinger.net> In-Reply-To: <CAGudoHGPw0Dmnv6ont8JGyLsT7qv%2BQqAFZO3tKOpNo3eN%2BJgLQ@mail.gmail.com> References: <61ca9df1b15c0e5477ff51196d0ec073@Leidinger.net> <CAGudoHG5Fgg4184SsXhzqYRR7VPaBXZoirGvyRyJX5ihX5YG-A@mail.gmail.com> <ed1f82dd26d3cc9ec9cc16505109ec40@Leidinger.net> <CAGudoHEP8TrSzz0TL-PsOx0WNc7z3042wJk-jhhVwhTyJ0VEQQ@mail.gmail.com> <88e837aeb5a65c1f001de2077fb7bcbd@Leidinger.net> <4d60bd12b482e020fd4b186a9ec1a250@Leidinger.net> <CAGudoHE7RPcHpQEqKbzRM8cJcYKue17=iPVv8iOfZq03h22tTA@mail.gmail.com> <73f7c9d3db8f117deb077fb17b1e352a@Leidinger.net> <CAGudoHGPw0Dmnv6ont8JGyLsT7qv%2BQqAFZO3tKOpNo3eN%2BJgLQ@mail.gmail.com>
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Am 2023-08-20 22:02, schrieb Mateusz Guzik: > On 8/20/23, Alexander Leidinger <Alexander@leidinger.net> wrote: >> Am 2023-08-20 19:10, schrieb Mateusz Guzik: >>> On 8/18/23, Alexander Leidinger <Alexander@leidinger.net> 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. Bye, Alexander. -- http://www.Leidinger.net Alexander@Leidinger.net: PGP 0x8F31830F9F2772BF http://www.FreeBSD.org netchild@FreeBSD.org : PGP 0x8F31830F9F2772BF
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