xfs perform a lot better than ext4 [WAS: Re: Two identical systems, radically different performance]

[sorry for resuming an old thread]

[cut]

>>> Question is... will that remove the performance penalty of HyperThreading?
>>
>> So I've added to my todo list to perform a test to verify this claim :)
>
> done.

on this box:

> in a brief: the box is dell a PowerEdge r720 with 16GB of RAM,
> the cpu is a Xeon 5620 with 6 core, the OS is installed on a raid
> (sata disk 7.2k rpm) and the PGDATA is on separate RAID 1 array
> (sas 15K rpm) and the controller is a PERC H710 (bbwc with a cache
> of 512 MB). (ubuntu 12.04)

with postgres 9.2.1 and $PGDATA on a ext4 formatted partition
i've got:

> those are the results:
>
> HT HT SYSFS DIS HT BIOS DISABLE
> -c -t r1 r2 r3 r1 r2 r3 r1 r2 r3
> 5 20K 1641 1831 1496 2020 1974 2033 2005 1988 1967
> 10 10K 2161 2134 2136 2277 2252 2216 1854 1824 1810
> 20 5k 2550 2508 2558 2417 2388 2357 1924 1928 1954
> 30 3333 2216 2272 2250 2333 2493 2496 1993 2009 2008
> 40 2.5K 2179 2221 2250 2568 2535 2500 2025 2048 2018
> 50 2K 2217 2213 2213 2487 2449 2604 2112 2016 2023

on the same machine with the same configuration,
having PGDATA on a xfs formatted partition gives me
a much better TPS.

e.g. pgbench -c 20 -t 5000 gives me 6305 TPS
(3 runs with "echo 3 > /proc/sys/vm/drop_caches && /etc/init.d/postgresql-9.2 restart"
in between).

Anybody else have experienced this kind of differences
between etx4 and xfs?

Andrea