Re: FSM patch - performance test - Mailing list pgsql-hackers

Heikki Linnakangas napsal(a):
> Tom Lane wrote:
>> Heikki Linnakangas <heikki.linnakangas@enterprisedb.com> writes:
>>> Zdenek Kotala wrote:
>>>> My conclusion is that new implementation is about 8% slower in OLTP 
>>>> workload.
>>
>>> Thanks. That's very disappointing :-(
>>
>> One thing that jumped out at me is that you call FreeSpaceMapExtendRel
>> every time a rel is extended by even one block.  I admit I've not
>> studied the data structure in any detail yet, but surely most such calls
>> end up being a no-op?  Seems like some attention to making a fast path
>> for that case would be helpful.
> 
> Yes, most of those calls end up being no-op. Which is exactly why I 
> would be surprised if those made any difference. It does call 
> smgrnblocks(), though, which isn't completely free...

It is not a problem. It is really strange. I'm using DTrace to count number of 
calls and number of calls is really small (I monitor only one backend). I have 
removed WAL logging and it does not help too.

> Zdenek, can you say off the top of your head whether the test was I/O 
> bound or CPU bound? What was the CPU utilization % during the test?

CPU is not problem it is mostly in idle time.

-bash-3.00# iostat 5   tty        sd1           ssd0          ssd1          nfs1           cpu tin tout kps tps serv
kpstps serv  kps tps serv  kps tps serv   us sy wt id   0    1   0   0    1    9   1   92    0   0    0    0   0    0
0  0  0 100   0   47   0   0    0  894 111    7    0   0    0    0   0    0    2  1  0 97   0   16   0   0    0  949
118   6    0   0    0    0   0    0    2  2  0 97   0   16   0   0    0  965 120    6    0   0    0    0   0    0    2
1 0 97   0   16   0   0    0  981 122    7    0   0    0    0   0    0    2  2  0 96   0   16   0   0    0  944 118
6   0   0    0    0   0    0    2  1  0 97   0   16   0   0    0  1202 149    7    0   0    0    0   0    0    3  2  0
95  0   16   0   0    0  1261 157    9    0   0    0    0   0    0    3  2  0 95   0   16   0   0    0  1357 168   14
0   0    0    0   0    0    3  2  0 95   0   16   0   0    0  1631 201   33    0   0    0    0   0    0    2  2  0 96
0  16   0   0    0  1973 246   48    0   0    0    0   0    0    2  2  0 96   0   16   0   0    0  2008 251   50    0
0   0    0   0    0    2  2  0 97   0   16   0   0    0  1956 241   45    0   0    0    0   0    0    2  2  0 97   0
16  0   0    0  2003 250   49    0   0    0    0   0    0    2  2  0 97
 

-bash-3.00# vmstat 1 kthr      memory            page            disk          faults      cpu r b w   swap  free  re
mfpi po fr de sr s1 sd sd --   in   sy   cs us sy id 0 0 0 28091000 31640552 3 4 0  0  0  0  0  0  1  0  0  359   72
206 0  0 100 0 0 0 27363144 27614576 3 28 0 16 16 0  0  0 60  0  0 1216 1134 1072  1  1 99 0 0 0 27363144 27614568 8 0
016 16  0  0  0 52  0  0 1099 1029  964  0  1 98 0 0 0 27363144 27614560 9 0 0  8  8  0  0  0 53  0  0 1143  896 1009
1 1 98 0 0 0 27363144 27614544 1 241 0 16 16 0 0  0 46  0  0 1042 1105  895  0  1 98 0 0 0 27363144 27614544 0 0 0 16
16 0  0  0 50  0  0 1078  860  924  0  0 99 0 0 0 27363144 27614552 10 0 0 16 16 0  0  0 56  0  0 1177  914 1033  1  1
980 0 0 27363144 27614536 0 0 0  8  8  0  0  0 25  0  0  726  554  603  0  0 99 0 0 0 27363144 27614528 1 0 0 16 16  0
0 0 65  0  0 1206 1159 1081  1  1 98 0 0 0 27363144 27614512 13 0 0 16 16 0  0  0 63  0  0 1256 1088 1094  1  1 99 0 0
027363144 27614512 0 0 0  8  8  0  0  0 37  0  0  920  797  779  0  1 99 0 0 0 27363144 27614504 6 0 0 16 16  0  0  0
58 0  0 1218 1074 1078  1  0 99 0 0 0 27363144 27614488 85 91 0 16 16 0 0  0 45  0  0  973 1344  833  1  1 99 0 0 0
2736314427614488 2 0 0 16 16  0  0  0 57  0  0 1164 1023 1036  1  1 99 0 0 0 27363144 27614472 4 0 0  8  8  0  0  0 47
0 0 1133  937  957  0  1 99
 


-- 
Zdenek Kotala              Sun Microsystems
Prague, Czech Republic     http://sun.com/postgresql