Re: 20% performance drop on PostgreSQL 9.2 from kernel 3.5.3 to3.6-rc5 on AMD chipsets

[Borislav Petkov]

On Fri, Sep 14, 2012 at 10:47:44AM +0300, 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]

Ok, I was able to reproduce it here too, albeit with different userspace
(debian testing and postgres 9.1).

I'll try a coarse bisection of the -rcs first, to see where the
regression appeared.

Thanks for reporting this.

-- 
Regards/Gruss,
Boris.
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