Re: git: 6468cd8e0ef9 - main - mount: add vnode usage per file system with mount -v
Date: Wed, 15 Jun 2022 16:09:12 UTC
Thanks. This fixes it. 16 simultaneous tar cf /dev/null /usr/obj on three
separate NFS clients:
Server:
Clients OpenOwner Opens LockOwner Locks
Delegs
3 48 54 0 0
0
Layouts
0
The load on the NFS server is ~ 0.5 to 2 on a four core machine with CPU
sys busy between 2% and 30%. Prior to this CPU sys was pegged at close to
100% with a load of 18. The regression has been resolved. Thanks.
--
Cheers,
Cy Schubert <Cy.Schubert@cschubert.com>
FreeBSD UNIX: <cy@FreeBSD.org> Web: http://www.FreeBSD.org
NTP: <cy@nwtime.org> Web: https://nwtime.org
e**(i*pi)+1=0
In message <Yqn1yOpENwgc588g@ambrisko.com>, Doug Ambrisko writes:
> On Wed, Jun 15, 2022 at 07:23:51AM -0700, Doug Ambrisko wrote:
> | On Wed, Jun 15, 2022 at 07:05:14AM -0700, Cy Schubert wrote:
> | | Can we revert this, please. It breaks NFSv4.
> |
> | It would be nice if you could try the proposed partial revert.
> | I'm planning to commit that shortly.
>
> It is in ce00b11940ab.
>
> Please let me know how that works.
>
> Thanks,
>
> Doug A.
> | | In message <20220615030833.79F9A9B@slippy.cwsent.com>, Cy Schubert writes
> :
> | | > In message <CAGudoHHbf3PTt_TXnKAtt5n_WOYpvA0dCb9HAiDLAL+yR3VCFQ@mail.gm
> ail.c
> | | > om>
> | | > , Mateusz Guzik writes:
> | | > > On 6/13/22, Doug Ambrisko <ambrisko@ambrisko.com> wrote:
> | | > > > On Mon, Jun 13, 2022 at 06:43:31PM +0200, Mateusz Guzik wrote:
> | | > > > | On 6/13/22, Doug Ambrisko <ambrisko@freebsd.org> wrote:
> | | > > > | > The branch main has been updated by ambrisko:
> | | > > > | >
> | | > > > | > URL:
> | | > > > | >
> | | > > > https://cgit.FreeBSD.org/src/commit/?id=6468cd8e0ef9d1d3331e9de26cd
> 2be59b
> | | > c7
> | | > > 78494
> | | > > > | >
> | | > > > | > commit 6468cd8e0ef9d1d3331e9de26cd2be59bc778494
> | | > > > | > Author: Doug Ambrisko <ambrisko@FreeBSD.org>
> | | > > > | > AuthorDate: 2022-06-13 14:56:38 +0000
> | | > > > | > Commit: Doug Ambrisko <ambrisko@FreeBSD.org>
> | | > > > | > CommitDate: 2022-06-13 14:56:38 +0000
> | | > > > | >
> | | > > > | > mount: add vnode usage per file system with mount -v
> | | > > > | >
> | | > > > | > This avoids the need to drop into the ddb to figure out vno
> de
> | | > > > | > usage per file system. It helps to see if they are or are
> not
> | | > > > | > being freed. Suggestion to report active vnode count was f
> rom
> | | > > > | > kib@
> | | > > > | >
> | | > > > | > Reviewed by: kib
> | | > > > | > Differential Revision: https://reviews.freebsd.org/D35436
> | | > > > | > ---
> | | > > > | > sbin/mount/mount.c | 7 +++++++
> | | > > > | > sys/kern/vfs_mount.c | 12 ++++++++++++
> | | > > > | > sys/sys/mount.h | 4 +++-
> | | > > > | > 3 files changed, 22 insertions(+), 1 deletion(-)
> | | > > > | >
> | | > > > | > diff --git a/sbin/mount/mount.c b/sbin/mount/mount.c
> | | > > > | > index 79d9d6cb0caf..bd3d0073c474 100644
> | | > > > | > --- a/sbin/mount/mount.c
> | | > > > | > +++ b/sbin/mount/mount.c
> | | > > > | > @@ -692,6 +692,13 @@ prmount(struct statfs *sfp)
> | | > > > | > xo_emit("{D:, }{Lw:fsid}{:fsid}", fsidb
> uf);
> | | > > > | > free(fsidbuf);
> | | > > > | > }
> | | > > > | > + if (sfp->f_nvnodelistsize != 0 || sfp->f_avnode
> count !=
> | | > > 0) {
> | | > > > | > + xo_open_container("vnodes");
> | | > > > | > + xo_emit("{D:,
> | | > > > | > }{Lwc:vnodes}{Lw:count}{w:count/%ju}{Lw:active}{:active/%ju}",
> | | > > > | > + (uintmax_t)sfp->f_nvnodelistsize,
> | | > > > | > + (uintmax_t)sfp->f_avnodecount);
> | | > > > | > + xo_close_container("vnodes");
> | | > > > | > + }
> | | > > > | > }
> | | > > > | > xo_emit("{D:)}\n");
> | | > > > | > }
> | | > > > | > diff --git a/sys/kern/vfs_mount.c b/sys/kern/vfs_mount.c
> | | > > > | > index 71a40fd97a9c..e3818b67e841 100644
> | | > > > | > --- a/sys/kern/vfs_mount.c
> | | > > > | > +++ b/sys/kern/vfs_mount.c
> | | > > > | > @@ -2610,6 +2610,8 @@ vfs_copyopt(struct vfsoptlist *opts, cons
> t char
> | | > > > *name,
> | | > > > | > void *dest, int len)
> | | > > > | > int
> | | > > > | > __vfs_statfs(struct mount *mp, struct statfs *sbp)
> | | > > > | > {
> | | > > > | > + struct vnode *vp;
> | | > > > | > + uint32_t count;
> | | > > > | >
> | | > > > | > /*
> | | > > > | > * Filesystems only fill in part of the structure for u
> pdates,
> | | > > we
> | | > > > | > @@ -2624,6 +2626,16 @@ __vfs_statfs(struct mount *mp, struct st
> atfs
> | | > > > *sbp)
> | | > > > | > sbp->f_version = STATFS_VERSION;
> | | > > > | > sbp->f_namemax = NAME_MAX;
> | | > > > | > sbp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
> | | > > > | > + sbp->f_nvnodelistsize = mp->mnt_nvnodelistsize;
> | | > > > | > +
> | | > > > | > + count = 0;
> | | > > > | > + MNT_ILOCK(mp);
> | | > > > | > + TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
> | | > > > | > + if (vrefcnt(vp) > 0) /* racy but does not matte
> r */
> | | > > > | > + count++;
> | | > > > | > + }
> | | > > > | > + MNT_IUNLOCK(mp);
> | | > > > | > + sbp->f_avnodecount = count;
> | | > > > | >
> | | > > > |
> | | > > > | libc uses statfs for dir walk (see gen/fts.c), most notably find
> | | > > > | immediately runs into it. As such the linear scan by default is a
> | | > > > | non-starter.
> | | > > > |
> | | > > > | I don't know if mount is the right place to dump this kind of inf
> o to
> | | > > > | begin with, but even so, it should only happen with a dedicated f
> lag.
> | | > > > |
> | | > > > | As statfs does not take any flags on its own, there is no way to
> | | > > > | prevent it from doing the above walk. Perhaps a dedicated sysctl
> which
> | | > > > | takes mount point id could do the walk instead, when asked.
> | | > > > |
> | | > > > | Short of making the walk optional I'm afraid this will have to be
> | | > > > reverted.
> | | > > >
> | | > > > Just to be clear, this isn't breaking things but is not optimal for
> | | > > > things that don't need this extra info.
> | | > > >
> | | > >
> | | > > It's not "not optimal", it's a significant overhead which taxes
> | | > > frequent users which don't benefit from it.
> | | >
> | | > Indeed this is not optimal. Since this revision NFSv4 performance has
> | | > tanked. An installworld over NFSv4 which used to take approximately 15
> | | > minutes took all night, not even finishing by morning. The NFS server,
> a 4
> | | > core machine, had a load average of 18 with three NFS clients attemptin
> g
> | | > installworld with nfsd using over 90% of the cycles on the machine. I w
> as
> | | > able to reproduce the problem by running a series of tar cf /dev/null
> | | > /usr/obj in parallel, on a single NFSv4 client to essentially DoS the N
> FSv4
> | | > server.
> | | >
> | | > The workaround was to fall back to NFSv3, which was unaffected by this
> | | > revision.
> | | >
> | | > I reached out to our resident NFS person (rmacklem@) who suggested
> | | > reverting this revision, restoring the network to pre-regression state.
> | | >
> | | > >
> | | > > For more data I plugged dtrace -n 'fbt::__vfs_statfs:entry {
> | | > > @[execname] = count(); }' while package building, then i got tons of
> | | > > hits:
> | | > > [snip]
> | | > > expr 13992
> | | > > install 14090
> | | > > dirname 14921
> | | > > mv 17404
> | | > > ghc-stage1 17577
> | | > > grep 18998
> | | > > xgcc 23832
> | | > > cpp 29282
> | | > > cc1 36961
> | | > > sh 70575
> | | > > rm 73904
> | | > > ld.lld 87784
> | | > > sed 88803
> | | > > c++ 98175
> | | > > cat 115811
> | | > > cc 449725
> | | > >
> | | > [...]
> | | > > --
> | | > > Mateusz Guzik <mjguzik gmail.com>
> | | > >
> | | >
> | | >
> | | > --
> | | > Cheers,
> | | > Cy Schubert <Cy.Schubert@cschubert.com>
> | | > FreeBSD UNIX: <cy@FreeBSD.org> Web: http://www.FreeBSD.org
> | | > NTP: <cy@nwtime.org> Web: https://nwtime.org
> | | >
> | | > e**(i*pi)+1=0
> | | >
> | | >
> | |