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

Regards, Nikolay.
Like Daniel said to you, I encourage to inform all your findings to the
LKML to
report all these problems.

Only one las t question: Did you tune the postgresql.conf for every
system? or
Did you use the default configuration ?

Best wishes
On 09/14/2012 04:45 AM, Daniel Farina wrote:
> On Fri, Sep 14, 2012 at 12:40 AM, Nikolay Ulyanitsky <lystor(at)gmail(dot)com> 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.
>

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