Re: 20% performance drop on PostgreSQL 9.2 from kernel 3.5.3 to 3.6-rc5 on AMD chipsets

On Fri, Sep 14, 2012 at 12:40 AM, Nikolay Ulyanitsky  wrote:
> Hi
> I compiled the 3.6-rc5 kernel with the same config from 3.5.3 and got
> the 15-20% performance drop of PostgreSQL 9.2 on AMD chipsets (880G,
> 990X).
>
> CentOS 6.3 x86_64
> PostgreSQL 9.2
> cpufreq scaling_governor - performance
>
> # /etc/init.d/postgresql initdb
> # echo "fsync = off" >> /var/lib/pgsql/data/postgresql.conf
> # /etc/init.d/postgresql start
> # su - postgres
> $ psql
> # create database pgbench;
> # \q
>
> # pgbench -i pgbench && pgbench -c 10 -t 10000 pgbench
> tps = 4670.635648 (including connections establishing)
> tps = 4673.630345 (excluding connections establishing)[/code]
>
> On kernel 3.5.3:
> tps = ~5800
>
> 1) Host 1 - 15-20% performance drop
> AMD Phenom(tm) II X6 1090T Processor
> MB: AMD 880G
> RAM: 16 Gb DDR3
> SSD: PLEXTOR PX-256M3 256Gb
>
> 2) Host 2 - 15-20% performance drop
> AMD Phenom(tm) II X6 1055T Processor
> MB: AMD 990X
> RAM: 32 Gb DDR3
> SSD: Corsair Performance Pro 128Gb
>
> 3) Host 3 - no problems - same performance
> Intel E6300
> MB: Intel® P43 / ICH10
> RAM: 4 Gb DDR3
> HDD: SATA 7200 rpm
>
> Kernel config - http://pastebin.com/cFpg5JSJ
>
> Any ideas?

Did you tell LKML? It seems like a kind of change that could be found
using git bisect of Linux, albiet laboriously.

-- 
fdr