Re: Re[2]: [PERFORM] SMP on a heavy loaded database

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> From: devnull(at)mail(dot)ua
> To: pgsql-performance(at)postgresql(dot)org
> Subject: [PERFORM] Re[2]: [PERFORM] SMP on a heavy loaded database
> Date: Fri, 4 Jan 2013 18:41:25 +0400
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> Пятница, 4 января 2013, 0:42 -07:00 от Scott Marlowe
> <scott(dot)marlowe(at)gmail(dot)com>:
> On Thu, Jan 3, 2013 at 4:45 PM, nobody nowhere
> <devnull(at)mail(dot)ua<http://sentmsg?compose&To=devnull%40mail.ua>> wrote:
> > Centos 5.X kernel 2.6.18-274
> > pgsql-9.1 from pgdg-91-centos.repo
> > relatively small database 3.2Gb
> > Lot of insert, update, delete.
> >
> > I see non balanced _User_ usage on 14 CPU, exclusively assigned to
> the hardware raid controller.
> > What I'm doing wrong, and is it possible somehow to fix?
> >
> > Thanks in advance.
> >
> > Andrew.
> >
> > # top -d 10.00 -b -n 2 -U postgres -c
> >
> > top - 23:18:19 up 453 days, 57 min, 3 users, load average: 0.55, 0.47, 0.42
> > Tasks: 453 total, 1 running, 452 sleeping, 0 stopped, 0 zombie
> > Cpu0 : 0.6%us, 0.1%sy, 0.0%ni, 99.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
> > Cpu1 : 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
> > Cpu2 : 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
> > Cpu3 : 1.2%us, 0.1%sy, 0.0%ni, 98.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
> > Cpu4 : 2.6%us, 0.4%sy, 0.0%ni, 96.8%id, 0.0%wa, 0.0%hi, 0.2%si, 0.0%st
> > Cpu5 : 0.8%us, 0.0%sy, 0.0%ni, 99.2%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
> > Cpu6 : 5.4%us, 0.2%sy, 0.0%ni, 94.2%id, 0.2%wa, 0.0%hi, 0.0%si, 0.0%st
> > Cpu7 : 3.3%us, 0.4%sy, 0.0%ni, 96.1%id, 0.0%wa, 0.0%hi, 0.2%si, 0.0%st
> > Cpu8 : 1.4%us, 0.3%sy, 0.0%ni, 98.2%id, 0.0%wa, 0.0%hi, 0.1%si, 0.0%st
> > Cpu9 : 0.0%us, 0.1%sy, 0.0%ni, 99.9%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
> > Cpu10 : 0.0%us, 0.1%sy, 0.0%ni, 99.9%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
> > Cpu11 : 1.6%us, 0.6%sy, 0.0%ni, 97.4%id, 0.0%wa, 0.0%hi, 0.4%si, 0.0%st
> > Cpu12 : 0.5%us, 0.1%sy, 0.0%ni, 99.4%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
> > Cpu13 : 1.4%us, 0.2%sy, 0.0%ni, 98.4%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
> > Cpu14 : 24.2%us, 0.8%sy, 0.0%ni, 74.5%id, 0.3%wa, 0.0%hi, 0.2%si, 0.0%st
> > Cpu15 : 0.7%us, 0.1%sy, 0.0%ni, 99.0%id, 0.0%wa, 0.1%hi, 0.1%si, 0.0%st
> > Mem: 16426540k total, 16356772k used, 69768k free, 215764k buffers
> > Swap: 4194232k total, 145280k used, 4048952k free, 14434356k cached
> >
>
> So how many concurrent users are accessing this db? pgsql assigns one
> process on one core so to speak. It can't spread load for one user
> over all cores.
> 64 php Fast-cgi processes over the Unix socket and about 20-30 over tcp

Are you running IRQ Balance ? The OS can pin process to the respective IRQ handler.