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

Compression 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 suggestion or opinion, please send an e-mail to us at linuxcompressed-devel@lists.sourceforge.net.

All algorithms tested at the same time

Acknowledgements: special thanks to Matthias Rosenkranz for helping us so much on these tests.

lmbench's memsize

   compressed cache - statistics
   -- algorithm --
   WKdm
   -- pages --
   27544
   -- size --
   min        | max        | mean     
          272 |       4368 |         380
   -- compression cycles --
   min        | max        | mean
        25422 |      96350 |       27907
   -- decompression cycles --
   min        | max        | mean
         9105 |      56499 |       10022

   compression ratio:        9%
   discarded pages:        232
   discarded ratio:          0%

   -- algorithm --
   WK4x4
   -- pages --
   27544
   -- size --
   min        | max        | mean     
          256 |       4352 |         355
   -- compression cycles --
   min        | max        | mean
        14929 |     106680 |       17775
   -- decompression cycles --
   min        | max        | mean
        17082 |      95238 |       18670

   compression ratio:        8%
   discarded pages:        194
   discarded ratio:          0%

   -- algorithm --
   LZO
   -- pages --
   27544
   -- size --
   min        | max        | mean     
           28 |       4117 |         121
   -- compression cycles --
   min        | max        | mean
        19338 |   14386215 |       24886
   -- decompression cycles --
   min        | max        | mean
         4505 |   14117430 |       13430

   compression ratio:        2%
   discarded pages:         73
   discarded ratio:          0%

user workload 1 (128M) - configuration

   compressed cache - statistics
   -- algorithm --
   WKdm
   -- pages --
   12178
   -- size --
   min        | max        | mean     
          272 |       4372 |        1636
   -- compression cycles --
   min        | max        | mean
        29096 |     151685 |       43095
   -- decompression cycles --
   min        | max        | mean
         9106 |     185539 |       17547
	 
   compression ratio:       39%
   discarded pages:       1080
   discarded ratio:          8%

   -- algorithm --
   WK4x4
   -- pages --
   12178
   -- size --
   min        | max        | mean     
          256 |       4352 |        1507
   -- compression cycles --
   min        | max        | mean
        14934 |     160511 |       44051
   -- decompression cycles --
   min        | max        | mean
        17088 |     133447 |       39195

   compression ratio:       36%
   discarded pages:        875
   discarded ratio:          7%

   -- algorithm --
   LZO
   -- pages --
   12178
   -- size --
   min        | max        | mean     
           28 |       4137 |        1115
   -- compression cycles --
   min        | max        | mean
        19422 |     948295 |       78174
   -- decompression cycles --
   min        | max        | mean
         4341 |     106010 |       18675

   compression ratio:       27%
   discarded pages:        338
   discarded ratio:          2%

user workload 1 (32M) with mem leak (realplayer used 106M virtual memory) - configuration

   compressed cache - statistics
   -- algorithm --
   WKdm
   -- pages --
   171455
   -- size --
   min        | max        | mean     
          272 |       4372 |        2174
   -- compression cycles --
   min        | max        | mean
        25451 |     162844 |       36692
   -- decompression cycles --
   min        | max        | mean
         9105 |     125635 |       17301

   compression ratio:       53%
   discarded pages:      44534
   discarded ratio:         25%

   -- algorithm --
   WK4x4
   -- pages --
   171455
   -- size --
   min        | max        | mean     
          256 |       4352 |        2069
   -- compression cycles --
   min        | max        | mean
        14930 |     144083 |       45692
   -- decompression cycles --
   min        | max        | mean
        17088 |     159373 |       37431

   compression ratio:       50%
   discarded pages:      42154
   discarded ratio:         24%

   compressed cache - statistics
   -- algorithm --
   LZO
   -- pages --
   171455
   -- size --
   min        | max        | mean     
           28 |       4141 |        1826
   -- compression cycles --
   min        | max        | mean
        19329 |     772210 |      115441
   -- decompression cycles --
   min        | max        | mean
         4289 |     108677 |       16951

   compression ratio:       44%
   discarded pages:      35066
   discarded ratio:         20%

user workload 1 (32M) - configuration

   compressed cache - statistics
   -- algorithm --
   WKdm
   -- pages --
   73962
   -- size --
   min        | max        | mean     
          272 |       4372 |        1728
   -- compression cycles --
   min        | max        | mean
        25507 |     194785 |       36846
   -- decompression cycles --
   min        | max        | mean
         9106 |     270884 |       17060

   compression ratio:       42%
   discarded pages:       7560
   discarded ratio:         10%

   -- algorithm --
   WK4x4
   -- pages --
   73962
   -- size --
   min        | max        | mean     
          256 |       4352 |        1605
   -- compression cycles --
   min        | max        | mean
        14934 |     186474 |       43362
   -- decompression cycles --
   min        | max        | mean
        17088 |     163901 |       38729

   compression ratio:       39%
   discarded pages:       6604
   discarded ratio:          8%

   -- algorithm --
   LZO
   -- pages --
   73962
   -- size --
   min        | max        | mean     
           28 |       4136 |        1261
   -- compression cycles --
   min        | max        | mean
        19324 |     781886 |       77076
   -- decompression cycles --
   min        | max        | mean
         4301 |     110314 |       17203

   compression ratio:       30%
   discarded pages:       3402
   discarded ratio:          4%

browsing with Netscape - configuration

   compressed cache - statistics
   -- algorithm --
   WKdm
   -- pages --
   7859
   -- size --
   min        | max        | mean     
          272 |       4372 |        2290
   -- compression cycles --
   min        | max        | mean
        34800 |     262040 |       48480
   -- decompression cycles --
   min        | max        | mean
        12591 |     308123 |       25139

   compression ratio:       55%
   discarded pages:       1665
   discarded ratio:         21%

   -- algorithm --
   WK4x4
   -- pages --
   7859
   -- size --
   min        | max        | mean     
          256 |       4352 |        1919
   -- compression cycles --
   min        | max        | mean
        15951 |     269938 |       46602
   -- decompression cycles --
   min        | max        | mean
        16970 |     375634 |       40223

   compression ratio:       46%
   discarded pages:       1535
   discarded ratio:         19%

   -- algorithm --
   LZO
   -- pages --
   7859
   -- size --
   min        | max        | mean     
           28 |       4118 |        1354
   -- compression cycles --
   min        | max        | mean
        19327 |     446295 |       70641
   -- decompression cycles --
   min        | max        | mean
         4274 |     217803 |       17889

   compression ratio:       33%
   discarded pages:        134
   discarded ratio:          1%

WKdm Results

make -j 32 bzlilo

   compressed cache - statistics for compressed pages (alg. WKdm)
   num_pages  min_size  max_size  mean_size  min_cycles  max_cycles  mean_cycles  discarded_pages
      431342       272      4332       1719       28382      151202         8431            28513

   compression_ratio: 42%
   max_comp_ratio: 6%
   min_comp_ratio: 105.8%
   discarded/num_ratio: 6.6%

browsing with netscape (full report)

   compressed cache - statistics for compressed pages (alg. WKdm)
   num_pages  min_size  max_size  mean_size  min_cycles  max_cycles  mean_cycles  discarded_pages
     5223       272      4372       2291       28397      250007           38055             1373

   Ratios:
   compression ratio (mean_size/PAGE_SIZE): 56%
   discarded ratio (discarded_pages/num_pages): 26%

LZO Results

browsing with netscape (full report)

   compressed cache - statistics for compressed pages (LZO algorithm)
   num_pages  min_size  max_size  mean_size  min_cycles  max_cycles  mean_cycles  discarded_pages
        8597        28      4116       1301       24420      615400        74675              122

   Ratios:
   compression ratio (mean/size/PAGE_SIZE): 32%
   discarded ratio (discarded_pages/num_pages): 1.4%

Page last updated on "Mon Jul 2 17:07:57 2001"
Send feedback to Rodrigo S. de Castro <rcastro@lists.sourceforge.net>