On Fri, Sep 14, 2012 at 12:40 AM, Nikolay Ulyanitsky <lystor@xxxxxxxxx> wrote:
Did you compile the AMD code on the AMD system?
We use a different open-source project that provides chemistry functionality, and discovered the hard way that the code optimizer is specific to each chip. Code compiled on Intel chips would sometimes run 50% slower on AMD chips (and vice versa). When we compiled the Intel code using Intel computers and AMD code using AMD computers, the performance difference disappeared.
There's probably an optimizer flag somewhere that would allow you to force it to compile for one chip or the other, but by default it seems to pick the one you're running on.
Craig
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).
Did you compile the AMD code on the AMD system?
We use a different open-source project that provides chemistry functionality, and discovered the hard way that the code optimizer is specific to each chip. Code compiled on Intel chips would sometimes run 50% slower on AMD chips (and vice versa). When we compiled the Intel code using Intel computers and AMD code using AMD computers, the performance difference disappeared.
There's probably an optimizer flag somewhere that would allow you to force it to compile for one chip or the other, but by default it seems to pick the one you're running on.
Craig
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?
Thx
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