vmdaemon CPU usage and poor performance in 10.0-RELEASE
Polyack, Steve
Steve.Polyack at intermedix.com
Wed Aug 20 14:55:48 UTC 2014
> -----Original Message-----
> From: Polyack, Steve
> Sent: Wednesday, August 20, 2014 9:14 AM
> To: Polyack, Steve; Alan Cox; freebsd-stable at freebsd.org
> Subject: RE: vmdaemon CPU usage and poor performance in 10.0-RELEASE
>
>
> > -----Original Message-----
> > From: owner-freebsd-stable at freebsd.org [mailto:owner-freebsd-
> > stable at freebsd.org] On Behalf Of Polyack, Steve
> > Sent: Tuesday, August 19, 2014 12:37 PM
> > To: Alan Cox; freebsd-stable at freebsd.org
> > Subject: RE: vmdaemon CPU usage and poor performance in 10.0-RELEASE
> >
> > > -----Original Message-----
> > > From: owner-freebsd-stable at freebsd.org [mailto:owner-freebsd-
> > > stable at freebsd.org] On Behalf Of Alan Cox
> > > Sent: Monday, August 18, 2014 6:07 PM
> > > To: freebsd-stable at 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 at freebsd.org [mailto:owner-freebsd-
> > > >> stable at freebsd.org] On Behalf Of Alan Cox
> > > >> Sent: Monday, August 18, 2014 3:05 PM
> > > >> To: freebsd-stable at 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 note.
> > > >>> 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 Wed04PM 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 about
> > > 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 now.
> >
> > 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, and
> > redis-2.8.11 are all in use here. I can't say that anything is unusual about
> the
> > configuration.
> >
>
> We are still seeing the issue. It seems to manifest once the "Free" memory
> 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 activity
> (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:
>
> 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
>
> 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
>
>
Another thing I've noticed is that this sysctl vm.stats counter is increasing 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
More information about the freebsd-stable
mailing list