Department of Computer Science
University of São Paulo
São Paulo, Brazil

Compression and Performance Statistics

On this page you can find some of our compression tests on swapped out pages in Linux 2.4. This page was created to help us out visualize and make some analysis on these data. WARNING: this material is still very raw and some numbers may not be correct due to unpredictable situations. If you have any suggestions or opinion, please send an e-mail to us at linuxcompressed-devel@lists.sourceforge.net.

Configuration

Acknowledgements: special thanks to Gian-Carlo Pascutto for running these tests on his machine.

Athlon 1 GHz
256 Mb RAM
256 Mb Swap
Kernels tested:
- 2.4.6 Linux Kernel + 0.18pre1 Compressed Cache
- 2.4.6 Linux Kernel
Compression Algorithm: WKdm

Test Run

Chess Program (First Test)

The software tested was a chessprogram, performing a proofnumbersearch. This consists of building up a game tree in RAM. The program will move along that tree, do some calculations, back up the results to the root, find a new node to work on and move to a a leaf again.

All tests were done on a freshly rebooted machine and repeated 3 times in sequence.

2.4.6 + 0.18pre1 comp cache 4096 pages (64 entry hashtable)

Run 1   122.8s
    2   115.3s
    3   121.5s

compressed pages   157207 
faulted in           6116
mean size:           1675
comp. cycles:       41709
decomp. cycles:     23083

compression ratio: 40%
discarded:         463 (0%)

2.4.6 + 0.18pre1 comp cache 4096 pages (128 entry hashtable)
```
Run 1   121.2s
    2   126.7s
    3   127.2s
      
```

2.4.6 + 0.18pre1 comp cache 8192 pages (128 entry hashtable)

Run 1   119.3s
    2   133.1s
    3   134.1s

compressed pages  184843
faulted in         11845
mean size:          1545
comp cycles:       40915
decomp cycles:     19703

compression ratio:    37%
discarded:           1279 (0%)

2.4.6 vanilla

Run 1   121.1s
    2   121.1s
    3   121.5s

Chess Program (Second Test)

2.4.6 + 0.18pre1 comp cache 4096 pages (128 entry hashtable, WKdm)

Run 1   121.2s
    2   125.6s
    3   127.9s
    4   132.6s
    5   127.3s

compressed cache - statistics
-- algorithm --
WKdm
-- compressed pages --
54626
-- compressed pages faulted in --
1586
-- size --
min        | max        | mean
       272 |       4092 |        1514
-- compression cycles --
min        | max        | mean
     32348 |     146297 |       40884
-- decompression cycles --
min        | max        | mean
     10587 |     132194 |       24813

compression ratio:       36%
discarded pages:        459
discarded ratio:          0%

pgswpin 24931
pgswpout 48055

2.4.6 + 0.18pre1 comp cache 4096 pages (128 entry hashtable, WK4x4)

Run 1   115.9s
    2   119.9s
    3   121.1s

compressed cache statistics
no pages have been compressed with WKdm

compressed cache - statistics
-- algorithm --
WK4x4
-- compressed pages --
54096
-- compressed pages faulted in --
2379
-- size --
min        | max        | mean
       256 |       4092 |        1106
-- compression cycles --
min        | max        | mean
     19294 |     143012 |       44440
-- decompression cycles --
min        | max        | mean
     20669 |     152950 |       39654

compression ratio:       27%
discarded pages:        436
discarded ratio:          0%

pgswpin 18589
pgswpout 42661

2.4.6 + 0.18pre1 comp cache 4096 pages (128 entry hashtable, LZO)

Run 1   119.4s
    2   132.8s
    3   131.1s

compressed cache statistics 
no pages have been compressed with WKdm

compressed cache statistics
no pages have been compressed with WK4x4

compressed cache - statistics
-- algorithm --   
LZO
-- compressed pages --
52787
-- compressed pages faulted in --
2423
-- size --
min        | max        | mean
        28 |       4095 |         884
-- compression cycles --
min        | max        | mean
     28075 |     263070 |       57762
-- decompression cycles --
min        | max        | mean
      9765 |     125187 |       20667

compression ratio:       21%
discarded pages:        168
discarded ratio:          0%

pgswpin 17792
pgswpout 41379

2.4.6 vanilla

Run 1   123.9s
    2   123.2s
    3   121.7s

pgswpin 28168
pgswpout 59582

Page last updated on "Tue Jun 4 06:58:54 2002"
Send feedback to Rodrigo S. de Castro <rcastro@lists.sourceforge.net>

Compression and Performance Statistics

Configuration

Test Run

Chess Program (First Test)

2.4.6 + 0.18pre1 comp cache 4096 pages (64 entry hashtable)

2.4.6 + 0.18pre1 comp cache 4096 pages (128 entry hashtable)

2.4.6 + 0.18pre1 comp cache 8192 pages (128 entry hashtable)

2.4.6 vanilla

Chess Program (Second Test)

2.4.6 + 0.18pre1 comp cache 4096 pages (128 entry hashtable, WKdm)

2.4.6 + 0.18pre1 comp cache 4096 pages (128 entry hashtable, WK4x4)

2.4.6 + 0.18pre1 comp cache 4096 pages (128 entry hashtable, LZO)

2.4.6 vanilla