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CPU resources real / user / system [message #25267]

Wed, 19 December 2007 12:03

yahbluez
Messages: 18
Registered: August 2007
Location: Germany

Junior Member

Gents,

i'm running OVZ on an xeon dual quad core system, that means 8 cores and a lot of memory (16G).

I try to find out the max usefull number of running VE.
Doing all the same small job.

Running VEs i got
(all values are seconds taken from time)

1VE
30real 11user 25system

2VE
37real 11user 36system

3VE
60real 11user 70system

4VE
97real 12user 124system

8VE
276real 14user 260system

I wonder why the amount of system time increases so dramatically.
Can't believe that 2VEs are the maximum number to get the highest troughput for this applikation.

Especially when i compare 1VE with a (nearly) 1:2 ratio of user:system with 2VEs or 8VEs where this ratio screws down to 1:19.

Any idea?

best regards and thank you for OVZ!

This is the conf i used:

# Primary parameters
NUMPROC="1280:1280"
AVNUMPROC="640:640"
NUMTCPSOCK="1280:1280"
NUMOTHERSOCK="1280:1280"
VMGUARPAGES="39226:9223372036854775807"

# Secondary parameters
KMEMSIZE="52496832:57746515"
TCPSNDBUF="12256064:17498944"
TCPRCVBUF="12256064:17498944"
OTHERSOCKBUF="6128032:11370912"
DGRAMRCVBUF="6128032:6128032"
OOMGUARPAGES="39226:9223372036854775807"
PRIVVMPAGES="235356:258891"

# Auxiliary parameters
LOCKEDPAGES="2563:2563"
SHMPAGES="23535:23535"
PHYSPAGES="0:9223372036854775807"
NUMFILE="20480:20480"
NUMFLOCK="1000:1100"
NUMPTY="128:128"
NUMSIGINFO="1024:1024"
DCACHESIZE="11452893:11796480"
NUMIPTENT="31:31"
DISKSPACE="167545:184300"
DISKINODES="744016:818418"
#
CPUUNITS="8888"
VE_ROOT="/vz/root/$VEID"
VE_PRIVATE="/vz/private/$VEID"
ORIGIN_SAMPLE="64"

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Re: CPU resources real / user / system [message #25273 is a reply to message #25267]

Wed, 19 December 2007 13:33

yahbluez
Messages: 18
Registered: August 2007
Location: Germany

Junior Member

maybe thee nourmous number of content switches produces this effect?

vmstat 1
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
74 0 44 170000 32884 9305788 0 0 0 0 4 4 0 3 96 0
76 0 44 115760 32884 9305912 0 0 0 0 2004 11873 6 94 0 0
91 0 44 156460 32884 9305732 0 0 0 0 1845 8331 3 97 0 0
87 0 44 121164 32884 9305748 0 0 0 0 1969 10529 5 95 0 0
77 0 44 164912 32884 9305812 0 0 0 0 2787 8056 4 96 0 0
129 0 44 130780 32884 9306240 0 0 0 0 2068 10177 3 97 0 0
61 0 44 131408 32884 9306916 0 0 0 0 1897 7083 9 91 0 0
124 0 44 145816 32884 9307076 0 0 0 0 1531 8757 2 98 0 0
71 0 44 112944 32892 9307332 0 0 0 0 2317 9516 6 94 0 0

kernel timer is set to 1000 at compile time.

Maybe 100 is better for a server?

thx
yahbluez

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Re: CPU resources real / user / system [message #25308 is a reply to message #25267]

Wed, 19 December 2007 19:24

dev
Messages: 1693
Registered: September 2005
Location: Moscow

Senior Member

it's really hard to ask your question, since technically you provided too little details.

what do you run and what do you measure? any exact commands?
do you run your command in VE or remotely or how?
and so on.

from what I can guess, you run the same app in 8 VEs,
all are loaded, so when you run 8 VEs instead of one, you should get 30*8 = 240 secs, but get 276.
is it the case?

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