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Thank you for you reply! “one of the indicators of that is that context switches per second
will start to jump up and the machine gets Sluggish” --> Here is my database server indicator: These is ther VMSTAT log
of my database server as below: 2010-04-07 04:03:15
procs
memory
swap io system
cpu 2010-04-07 04:03:15 r b
swpd free buff cache si
so bi bo in
cs us sy id wa 2010-04-07 14:04:27 3
0 0 2361272 272684 3096148
0 0 3 1445 973
14230 7 8 84 0 2010-04-07 14:05:27 2
0 0 2361092 272684 3096220
0 0 3 1804 1029 31852 8
10 81 1 2010-04-07 14:06:27 1
0 0 2362236 272684 3096564
0 0 3 1865 1135 19689
9 9 81 0 2010-04-07 14:07:27 1
0 0 2348400 272720 3101836
0 0 3 1582 1182 149461 15 17
67 0 2010-04-07 14:08:27 3
0 0 2392028 272840 3107600
0 0 3 3093 1275 203196 24 23
53 1 2010-04-07 14:09:27 3
1 0 2386224 272916 3107960
0 0 3 2486 1331 193299 26 22
52 0 2010-04-07 14:10:27 34
0 0 2332320 272980 3107944
0 0 3 1692 1082 214309 24 22
54 0 2010-04-07 14:11:27 1
0 0 2407432 273028 3108092
0 0 6 2770 1540 76643 29 13
57 1 2010-04-07 14:12:27 9
0 0 2358968 273104 3108388
0 0 7 2639 1466 10603 22
6 72 1 My postgres version: My OS version: Linux version My CPU: processor
: 7 vendor_id
: GenuineIntel cpu
family : 15 model
: 6 model
name : Intel(R) Xeon(TM) CPU 3.40GHz stepping
: 8 cpu
MHz : 3400.262 cache
size : 1024 KB physical
id : 1 I donnt know what make the “context-switching” storm ？ How should I investigate the real reason ? Could you please give me some
advice ? Thank you ! -----邮件原件----- > RD黄永卫 wrote: >> >> Anybody have the test case of “ context-switching issue on Xeon” from >> Tm lane ？ >> > > That takes me back: >
http://archives.postgresql.org/pgsql-performance/2004-04/msg00280.php > > That's a problem seen on 2004 era Xeon
processors, and with PostgreSQL > 7.4. I doubt it has much relevance nowadays,
given a) that whole area of > the code was rewritten for PostgreSQL 8.1, and b)
today's Xeons are > nothing like 2004's Xeons. It's important to appreciate that all improvements in
scalability for xeons, opterons, and everything else has mostly just
moved further along to the right on the graph where you start doing
more context switching than work, and the performance falls
off. The same way that (sometimes) throwing more cores at a problem can
help. For most office sized pgsql servers there's still a real
possibility of having a machine getting slammed and one of the indicators of
that is that context switches per second will start to jump up and
the machine gets sluggish. For 2 sockets Intel rules the roost. I'd imagine
AMD's much faster bus architecture for >2 sockets would make them the
winner, but I haven't had a system like that to test, either Intel
or AMD. |
