Date: Tue, 20 Nov 2007 18:15:17 +0100 From: "Ivan Voras" <ivoras@freebsd.org> To: "Alexey Popov" <lol@chistydom.ru> Cc: freebsd-stable@freebsd.org Subject: Re: 2 x quad-core system is slower that 2 x dual core on FreeBSD Message-ID: <9bbcef730711200915n12e37efcs67cf260641b9baab@mail.gmail.com> In-Reply-To: <47430AE8.7050408@chistydom.ru> References: <4741905E.8050300@chistydom.ru> <fhs3s5$knj$1@ger.gmane.org> <47419AB3.5030008@chistydom.ru> <fhs7db$2es$1@ger.gmane.org> <4741B3DE.2000009@chistydom.ru> <fhsl0v$n85$1@ger.gmane.org> <47430AE8.7050408@chistydom.ru>
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On 20/11/2007, Alexey Popov <lol@chistydom.ru> wrote:
> CPU states: 5.9% user, 0.0% nice, 81.3% system, 0.0% interrupt, 12.8% idle
> CPU states: 82.2% user, 0.0% nice, 13.8% system, 0.0% interrupt, 4.0% idle
Interesting coincidence: 1 CPU generates almost 8x less "sys time" then 8 CPUs.
But it seems that you have found something real. Inspired by your
problem I've done a simple measurement ("ab") on a 4-CPU (2x2 core
Opterons 2216 HE, PAE) machine I maintain, under these circumstances:
- a "heavy" PHP application
- FastCGI
- in this case, load of 4 clients
- on 6-STABLE
and I'm reporting similar findings:
last pid: 2254; load averages: 1.43, 0.92, 0.69 up 71+08:23:06 18:00:31
153 processes: 8 running, 144 sleeping, 1 zombie
CPU states: 38.8% user, 0.0% nice, 48.4% system, 3.2% interrupt, 9.6% idle
Mem: 2321M Active, 1135M Inact, 313M Wired, 139M Cache, 112M Buf, 93M Free
Swap: 4500M Total, 336K Used, 4500M Free
PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND
2208 www 1 99 0 115M 19808K RUN 1 0:06 36.83% php-cgi
2207 www 1 100 0 114M 19348K RUN 3 0:05 32.66% php-cgi
1715 www 1 99 0 115M 23672K CPU0 0 0:24 27.83% php-cgi
1710 www 1 101 0 114M 23460K RUN 1 0:31 22.17% php-cgi
1882 www 1 99 0 115M 23392K CPU2 3 0:18 21.34% php-cgi
1718 www 1 4 0 114M 22556K sbwait 0 0:21 19.14% php-cgi
2677 pgsql 1 4 0 977M 55768K sbwait 0 0:00 28.00% postgres
We are not so performance bound as you so I didn't do measurements
earlier. I cannot "play" with settings on this machine as it is in
production, but ~~50% sys time (the measurement changes around 45% +/-
10%) seems too much.
On another 4-CPU machine (2x2 Xeons 5110, AMD64) with the same
application and benchmark setup, but RELENG_7, which is not yet in
production, the results are slightly different:
last pid: 66564; load averages: 1.87, 0.48, 0.18 up 15+05:27:03 17:09:09
113 processes: 9 running, 104 sleeping
CPU states: 49.0% user, 0.0% nice, 28.8% system, 0.0% interrupt, 22.1% idle
Mem: 555M Active, 295M Inact, 884M Wired, 98M Cache, 213M Buf, 135M Free
Swap: 2047M Total, 2047M Free
PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND
66557 www 1 109 0 105M 25340K RUN 3 0:14 64.99% php-cgi
66559 www 1 109 0 105M 25308K RUN 2 0:14 62.99% php-cgi
66561 www 1 98 0 105M 22196K RUN 0 0:01 12.99% php-cgi
66562 www 1 98 0 105M 22196K RUN 1 0:01 11.96% php-cgi
59043 nobody 1 47 0 7012K 3744K select 2 0:27 5.96% sqlcached
774 pgsql 1 44 0 437M 112M select 2 3:55 0.00% postgres
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