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Date:      Wed, 20 Aug 2014 09:55:43 -0500
From:      "Polyack, Steve" <Steve.Polyack@intermedix.com>
To:        Alan Cox <alc@rice.edu>, "freebsd-stable@freebsd.org" <freebsd-stable@freebsd.org>
Subject:   RE: vmdaemon CPU usage and poor performance in 10.0-RELEASE
Message-ID:  <4D557EC7CC2A544AA7C1A3B9CBA2B3672609CF31F0@exchange03.epbs.com>
In-Reply-To: <4D557EC7CC2A544AA7C1A3B9CBA2B3672609CF2F8F@exchange03.epbs.com>
References:  <4D557EC7CC2A544AA7C1A3B9CBA2B36726098846B4@exchange03.epbs.com> <20140813152522.GI9400@home.opsec.eu> <4D557EC7CC2A544AA7C1A3B9CBA2B36726098847AF@exchange03.epbs.com> <CAJUyCcNoTJ3xqkC_Prz3N%2BApEqYy3Mi2gA%2BuDo33dczaTMONrA@mail.gmail.com> <4D557EC7CC2A544AA7C1A3B9CBA2B3672609BBA3C4@exchange03.epbs.com> <53F24E5B.1010809@rice.edu> <4D557EC7CC2A544AA7C1A3B9CBA2B3672609BBA64F@exchange03.epbs.com> <53F2790C.20703@rice.edu> <4D557EC7CC2A544AA7C1A3B9CBA2B3672609CF28E5@exchange03.epbs.com> <4D557EC7CC2A544AA7C1A3B9CBA2B3672609CF2F8F@exchange03.epbs.com>

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> -----Original Message-----
> From: Polyack, Steve
> Sent: Wednesday, August 20, 2014 9:14 AM
> To: Polyack, Steve; Alan Cox; freebsd-stable@freebsd.org
> Subject: RE: vmdaemon CPU usage and poor performance in 10.0-RELEASE
>=20
>=20
> > -----Original Message-----
> > From: owner-freebsd-stable@freebsd.org [mailto:owner-freebsd-
> > stable@freebsd.org] On Behalf Of Polyack, Steve
> > Sent: Tuesday, August 19, 2014 12:37 PM
> > To: Alan Cox; freebsd-stable@freebsd.org
> > Subject: RE: vmdaemon CPU usage and poor performance in 10.0-RELEASE
> >
> > > -----Original Message-----
> > > From: owner-freebsd-stable@freebsd.org [mailto:owner-freebsd-
> > > stable@freebsd.org] On Behalf Of Alan Cox
> > > Sent: Monday, August 18, 2014 6:07 PM
> > > To: freebsd-stable@freebsd.org
> > > Subject: Re: vmdaemon CPU usage and poor performance in 10.0-
> RELEASE
> > >
> > > On 08/18/2014 16:29, Polyack, Steve wrote:
> > > >> -----Original Message-----
> > > >> From: owner-freebsd-stable@freebsd.org [mailto:owner-freebsd-
> > > >> stable@freebsd.org] On Behalf Of Alan Cox
> > > >> Sent: Monday, August 18, 2014 3:05 PM
> > > >> To: freebsd-stable@freebsd.org
> > > >> Subject: Re: vmdaemon CPU usage and poor performance in 10.0-
> > RELEASE
> > > >>
> > > >> On 08/18/2014 13:42, Polyack, Steve wrote:
> > > >>> Excuse my poorly formatted reply at the moment, but this seems to
> > > have
> > > >> fixed our problems.  I'm going to update the bug report with a not=
e.
> > > >>> Thanks Alan!
> > > >> You're welcome.  And, thanks for letting me know of the outcome.
> > > >>
> > > > Actually, I may have spoken too soon, as it looks like we're seeing
> > > vmdaemon tying up the system again:
> > > > root                6  100.0  0.0        0       16  -  DL   Wed04P=
M      4:37.95
> > [vmdaemon]
> > > >
> > > > Is there anything I can check to help narrow down what may be the
> > > problem?  KTrace/truss on the "process" doesn't give any information,=
 I
> > > suppose because it's actually a kernel thread.
> > >
> > > Can you provide the full output of top?  Is there anything unusual ab=
out
> > > the hardware or software configuration?
> >
> > This may have just been a fluke (maybe NFS caching the old vm_pageout.c
> > during the first source build).  We've rebuilt and are monitoring it no=
w.
> >
> > The hardware consists of a few Dell PowerEdge R720xd servers with 256GB
> > of RAM and array of SSDs (no ZFS).  64GB is dedicated to postgres
> > shared_buffers right now. FreeBSD 10, PostgreSQL 9.3, Slony-I v2.2.2, a=
nd
> > redis-2.8.11 are all in use here.  I can't say that anything is unusual=
 about
> the
> > configuration.
> >
>=20
> We are still seeing the issue.  It seems to manifest once the "Free" memo=
ry
> gets under 10GB (of 256GB on the system), even though ~200GB of this is
> classified as Inactive.  For us, this was about 7 hours of database activ=
ity
> (initial replication w/ slony).  Right now vmdaemon is consuming 100% CPU
> and shows 671:34 CPU time when it showed 0:00 up until the problem
> manifested.  The full top output (that fits on my screen) is below:
>=20
> last pid: 62309;  load averages:  4.05,  4.24,  4.10
> up 0+22:34:31  09:08:43
> 159 processes: 8 running, 145 sleeping, 1 waiting, 5 lock
> CPU: 14.5% user,  0.0% nice,  4.9% system,  0.0% interrupt, 80.5% idle
> Mem: 26G Active, 216G Inact, 4122M Wired, 1178M Cache, 1632M Buf, 2136M
> Free
> Swap: 32G Total, 32G Free
>=20
>   PID USERNAME       THR PRI NICE   SIZE    RES STATE   C   TIME    WCPU
> COMMAND
>    11 root            32 155 ki31     0K   512K CPU31  31 669.6H 2934.23%=
 idle
>     6 root             1 -16    -     0K    16K CPU19  19 678:57 100.00% =
vmdaemon
>  1963 pgsql            1  45    0 67538M   208M CPU0    0 121:46  17.38% =
postgres
>  2037 pgsql            1  77    0 67536M  2200K *vm ob 14   6:24  15.97% =
postgres
>  1864 pgsql            1  31    0 67536M  1290M semwai  4 174:41  15.19% =
postgres
>  1996 pgsql            1  38    0 67538M   202M semwai 16 120:27  15.09% =
postgres
>  1959 pgsql            1  39    0 67538M   204M CPU27  27 117:30  15.09% =
postgres
>  1849 pgsql            1  32    0 67536M  1272M semwai 23 126:22  13.96% =
postgres
>  1997 pgsql            1  31    0 67538M   206M CPU30  30 122:26  11.77% =
postgres
>  2002 pgsql            1  34    0 67538M   182M sbwait 11  55:20  11.28% =
postgres
>  1961 pgsql            1  32    0 67538M   206M CPU12  12 121:47  10.99% =
postgres
>  1964 pgsql            1  30    0 67538M   206M semwai 28 122:08   9.86% =
postgres
>  1962 pgsql            1  29    0 67538M  1286M sbwait  2  45:49   7.18% =
postgres
>  1752 root             1  22    0 78356K  8688K CPU2    2 175:46   6.88% =
snmpd
>  1965 pgsql            1  25    0 67538M   207M semwai  9 120:55   6.59% =
postgres
>  1960 pgsql            1  23    0 67538M   177M semwai  6  52:42   4.88% =
postgres
>  1863 pgsql            1  25    0 67542M   388M semwai 25   9:12   2.20% =
postgres
>  1859 pgsql            1  22    0 67538M  1453M *vm ob 20   6:13   2.10% =
postgres
>  1860 pgsql            1  22    0 67538M  1454M sbwait  8   6:08   1.95% =
postgres
>  1848 pgsql            1  21    0 67586M 66676M *vm ob 30 517:07   1.66% =
postgres
>  1856 pgsql            1  22    0 67538M   290M *vm ob 15   5:39   1.66% =
postgres
>  1846 pgsql            1  21    0 67538M   163M sbwait 15   5:46   1.46% =
postgres
>  1853 pgsql            1  21    0 67538M   110M sbwait 30   8:54   1.17% =
postgres
>  1989 pgsql            1  23    0 67536M  5180K sbwait 18   1:41   0.98% =
postgres
>     5 root             1 -16    -     0K    16K psleep  6   9:33   0.78% =
pagedaemon
>  1854 pgsql            1  20    0 67538M   338M sbwait 22   5:38   0.78% =
postgres
>  1861 pgsql            1  20    0 67538M   286M sbwait 15   6:13   0.68% =
postgres
>  1857 pgsql            1  20    0 67538M  1454M semwai 10   6:19   0.49% =
postgres
>  1999 pgsql            1  36    0 67538M   156M *vm ob 28 120:56   0.39% =
postgres
>  1851 pgsql            1  20    0 67538M   136M sbwait 22   5:48   0.39% =
postgres
>  1975 pgsql            1  20    0 67536M  5688K sbwait 25   1:40   0.29% =
postgres
>  1858 pgsql            1  20    0 67538M   417M sbwait  3   5:55   0.20% =
postgres
>  2031 pgsql            1  20    0 67536M  5664K sbwait  5   3:26   0.10% =
postgres
>  1834 root            12  20    0 71892K 12848K select 20  34:05   0.00% =
slon
>    12 root            78 -76    -     0K  1248K WAIT    0  25:47   0.00% =
intr
>  2041 pgsql            1  20    0 67536M  5932K sbwait 14  12:50   0.00% =
postgres
>  2039 pgsql            1  20    0 67536M  5960K sbwait 17   9:59   0.00% =
postgres
>  2038 pgsql            1  20    0 67536M  5956K sbwait  6   8:21   0.00% =
postgres
>  2040 pgsql            1  20    0 67536M  5996K sbwait  7   8:20   0.00% =
postgres
>  2032 pgsql            1  20    0 67536M  5800K sbwait 22   7:03   0.00% =
postgres
>  2036 pgsql            1  20    0 67536M  5748K sbwait 23   6:38   0.00% =
postgres
>  1812 pgsql            1  20    0 67538M 59185M select  1   5:46   0.00% =
postgres
>  2005 pgsql            1  20    0 67536M  5788K sbwait 23   5:14   0.00% =
postgres
>  2035 pgsql            1  20    0 67536M  4892K sbwait 18   4:52   0.00% =
<postgres>
>  1852 pgsql            1  21    0 67536M  1230M semwai  7   4:47   0.00% =
postgres
>    13 root             3  -8    -     0K    48K -      28   4:46   0.00% =
geom
>=20
>=20

Another thing I've noticed is that this sysctl vm.stats counter is increasi=
ng fairly rapidly:
# sysctl vm.stats.vm.v_pdpages && sleep 1 && sysctl vm.stats.vm.v_pdpages
vm.stats.vm.v_pdpages: 3455264541
vm.stats.vm.v_pdpages: 3662158383

Also, to demonstrate what kind of problems this seems to cause:
# time sleep 1

real	0m18.288s
user	0m0.001s
sys	0m0.004s

Steve



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