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

AMD K6-2 400 MHz
256 Mb RAM
256 Mb Swap
Kernel Host: 2.4.6
Kernels tested (all UML patched):
- 2.4.6 Linux Kernel + 2.4.6-4um UML patch + 0.17 Compressed Cache (unneeded debug tests have been commented)
- 2.4.6 Linux Kernel + 2.4.6-4um UML patch
UML configuration: 16 Mb RAM + 32 Mb Swap file
Compression Algorithm: WKdm

Tests Run (from Memtest Suite)

mmap001

1 time

command:
```
time ./mmap001 40
```

2.4.6 + 0.17 comp cache 500 pages (unneeded debug tests commented)

real    0m15.098s
user    0m0.450s
sys     0m1.950s

pgpgin = 9798
pgpgout = 83570
pswpin = 1
pswpout = 0

compressed cache - statistics
-- algorithm --
WKdm
-- pages --
240
-- size --
min        | max        | mean     
       276 |       3800 |        1271
-- compression cycles --
min        | max        | mean
     26250 |    5270276 |       57021
-- decompression cycles --
min        | max        | mean
     15884 |      47395 |        8110

compression ratio:       31%
discarded pages:          5
discarded ratio:          2%

2.4.6 vanilla

real    0m18.035s
user    0m0.650s
sys     0m2.050s

pgpgin = 10900
pgpgout = 85540
pswpin = 160
pswpout = 238

mmap001

26 times

command:

time for i in `seq 0 25`; do echo $i; ./mmap001 40; done

2.4.6 + 0.17 comp cache 500 pages (unneeded debug tests commented)


real    7m27.819s
user    0m14.650s
sys     1m0.450s

pgpgin = 71344
pgpgout = 2149558
pswpin = 1
pswpout = 0

compressed cache - statistics
-- algorithm --
WKdm
-- pages --
1420
-- size --
min        | max        | mean     
       276 |       3800 |        1440
-- compression cycles --
min        | max        | mean
     24700 |  122645491 |      125089
-- decompression cycles --
min        | max        | mean
     14548 |     235441 |       26516

compression ratio:       35%
discarded pages:         30
discarded ratio:          2%

2.4.6 vanilla

real    8m16.112s
user    0m14.950s
sys     1m9.700s

pgpgin = 91120
pgpgout = 2158240
pswpin = 2705
pswpout = 1156

fillmem

1 time

command:
```
time ./fillmem 40
```

2.4.6 + 0.17 comp cache 500 pages (unneeded debug tests commented)

   
real    0m21.683s
user    0m0.650s
sys     0m2.050s

pgpgin = 56318
pgpgout = 81144
pswpin = 5264
pswpout = 10099

compressed cache - statistics
-- algorithm --
WKdm
-- pages --
15183
-- size --
min        | max        | mean     
       272 |       3800 |         785
-- compression cycles --
min        | max        | mean
     25146 |   10367280 |       35684
-- decompression cycles --
min        | max        | mean
     12086 |    6405975 |       21052

compression ratio:       19%
discarded pages:          5
discarded ratio:          0%

2.4.6 vanilla

real    0m21.511s
user    0m0.650s
sys     0m3.200s

pgpgin = 66460
pgpgout = 109988
pswpin = 6982
pswpout = 13709

fillmem

26 times

command:

time for i in `seq 0 25`; do echo $i; ./fillmem 40; done

2.4.6 + 0.17 comp cache 500 pages (unneeded debug tests commented)

real    8m33.099s
user    0m17.450s
sys     0m57.350s

pgpgin = 1225982
pgpgout = 2033100
pswpin = 132088
pswpout = 254059

compressed cache - statistics
-- algorithm --
WKdm
-- pages --
394981
-- size --
min        | max        | mean     
       272 |       3800 |         777
-- compression cycles --
min        | max        | mean
     24344 |   69949099 |       36420
-- decompression cycles --
min        | max        | mean
     11958 |   42508213 |       20441

compression ratio:       18%
discarded pages:          5
discarded ratio:          0%

2.4.6 vanilla

real    7m35.063s
user    0m24.500s
sys     1m3.350s

pgpgin = 1536070
pgpgout = 2863722
pswpin = 180574
pswpout = 357890

Page last updated on "Tue Jun 4 06:57:38 2002"
Send feedback to Rodrigo S. de Castro <rcastro@lists.sourceforge.net>