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

From Jean-David Beyer
Subject Re: xfs perform a lot better than ext4 [WAS: Re: Two identical systems, radically different performance]
Date
Msg-id 50BF7B7C.9000204@verizon.net
Whole thread Raw
In response to xfs perform a lot better than ext4 [WAS: Re: Two identical systems, radically different performance]  (Andrea Suisani <sickpig@opinioni.net>)
Responses Re: xfs perform a lot better than ext4 [WAS: Re: Two identical systems, radically different performance]  (Claudio Freire <klaussfreire@gmail.com>)
Re: xfs perform a lot better than ext4 [WAS: Re: Two identical systems, radically different performance]  (Andrew Dunstan <andrew@dunslane.net>)
List pgsql-performance
On 12/05/2012 10:34 AM, Andrea Suisani wrote:
[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



I thought that postgreSQL did its own journalling, if that is the proper term, so why not use an ext2 file system to lower overhead?

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