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Re: Choosing a header compression algorithm

From: Mark Nottingham <mnot@mnot.net>
Date: Fri, 22 Mar 2013 17:32:06 +1100
Message-Id: <A14105FB-ED1A-4B70-8840-9648847BCC3A@mnot.net>
To: "ietf-http-wg@w3.org Group" <ietf-http-wg@w3.org>

On 21/03/2013, at 6:11 PM, Mark Nottingham <mnot@mnot.net> wrote:

> 1) We need to do apples-to-apples comparison of these compressors to see how they behave under a range of constraints (especially, memory).

To this point, a few runs across the header corpus that I collected (http_samples/mnot/*.har), using the current implementations (again, we need to verify these are honouring these limits correctly, and I believe headerdiff is going to be updated):

16384 Byte Buffer
----------------------

* TOTAL: 5948 req messages
                                        size  time | ratio min   max   std
                         http1     3,460,925  0.22 | 1.00  1.00  1.00  0.00
  delta2 (max_byte_size=16384)       630,668 15.89 | 0.18  0.03  0.76  0.11
     headerdiff (buffer=16384)     1,699,918  9.65 | 0.49  0.03  0.90  0.21

* TOTAL: 5948 res messages
                                        size  time | ratio min   max   std
                         http1     2,186,162  0.26 | 1.00  1.00  1.00  0.00
  delta2 (max_byte_size=16384)       575,345 24.39 | 0.26  0.02  1.06  0.12
     headerdiff (buffer=16384)       877,106 24.76 | 0.40  0.04  0.93  0.14

[ Note that the efficiency actually goes *down* on headerdiff for requests when the buffer is larger here; Herve, any idea what's happening there? ]

8192 Byte Buffer
----------------------

* TOTAL: 5948 req messages
                                       size  time | ratio min   max   std
                        http1     3,460,925  0.24 | 1.00  1.00  1.00  0.00
  delta2 (max_byte_size=8192)       646,431 15.78 | 0.19  0.03  0.76  0.12
     headerdiff (buffer=8192)     1,378,622  6.95 | 0.40  0.03  0.92  0.20

* TOTAL: 5948 res messages
                                       size  time | ratio min   max   std
                        http1     2,186,162  0.43 | 1.00  1.00  1.00  0.00
  delta2 (max_byte_size=8192)       592,260 20.28 | 0.27  0.02  1.06  0.12
     headerdiff (buffer=8192)       914,362 15.55 | 0.42  0.05  0.93  0.14


4096 Byte Buffer
----------------------

* TOTAL: 5948 req messages
                                       size  time | ratio min   max   std
                        http1     3,460,925  0.18 | 1.00  1.00  1.00  0.00
  delta2 (max_byte_size=4096)       665,642 13.35 | 0.19  0.03  0.77  0.12
     headerdiff (buffer=4096)     1,406,429  3.92 | 0.41  0.03  0.88  0.18

* TOTAL: 5948 res messages
                                       size  time | ratio min   max   std
                        http1     2,186,162  0.21 | 1.00  1.00  1.00  0.00
  delta2 (max_byte_size=4096)       610,764 15.48 | 0.28  0.02  1.06  0.13
     headerdiff (buffer=4096)     1,009,185  7.58 | 0.46  0.05  0.93  0.13

2048 Byte Buffer
----------------------

* TOTAL: 5948 req messages
                                       size  time | ratio min   max   std
                        http1     3,460,925  0.18 | 1.00  1.00  1.00  0.00
  delta2 (max_byte_size=2048)       692,579 11.66 | 0.20  0.03  0.77  0.12
     headerdiff (buffer=2048)     1,632,783  2.94 | 0.47  0.03  0.90  0.19

* TOTAL: 5948 res messages
                                       size  time | ratio min   max   std
                        http1     2,186,162  0.20 | 1.00  1.00  1.00  0.00
  delta2 (max_byte_size=2048)       633,785 12.47 | 0.29  0.02  1.22  0.13
     headerdiff (buffer=2048)     1,088,829  4.75 | 0.50  0.05  0.93  0.13

1024 Byte Buffer
----------------------

* TOTAL: 5948 req messages
                                       size  time | ratio min   max   std
                        http1     3,460,925  0.22 | 1.00  1.00  1.00  0.00
  delta2 (max_byte_size=1024)       752,380 11.92 | 0.22  0.03  0.84  0.13
     headerdiff (buffer=1024)     1,700,325  1.82 | 0.49  0.03  0.91  0.19

* TOTAL: 5948 res messages
                                       size  time | ratio min   max   std
                        http1     2,186,162  0.23 | 1.00  1.00  1.00  0.00
  delta2 (max_byte_size=1024)       671,975 11.42 | 0.31  0.02  1.22  0.13
     headerdiff (buffer=1024)     1,118,599  3.53 | 0.51  0.05  0.93  0.13

512 Byte Buffer
---------------------

* TOTAL: 5948 req messages
                                      size  time | ratio min   max   std
                       http1     3,460,925  0.17 | 1.00  1.00  1.00  0.00
  delta2 (max_byte_size=512)     1,058,090 14.23 | 0.31  0.04  0.83  0.15
     headerdiff (buffer=512)     2,120,833  1.43 | 0.61  0.03  0.93  0.16

* TOTAL: 5948 res messages
                                      size  time | ratio min   max   std
                       http1     2,186,162  0.14 | 1.00  1.00  1.00  0.00
  delta2 (max_byte_size=512)       721,525 12.22 | 0.33  0.03  1.22  0.13
     headerdiff (buffer=512)     1,199,608  2.09 | 0.55  0.05  0.93  0.12

256 Byte Buffer
---------------------

* TOTAL: 5948 req messages
                                      size  time | ratio min   max   std
                       http1     3,460,925  0.18 | 1.00  1.00  1.00  0.00
  delta2 (max_byte_size=256)     1,517,520 18.62 | 0.44  0.04  0.84  0.19
     headerdiff (buffer=256)     2,444,376  1.32 | 0.71  0.08  0.95  0.13

* TOTAL: 5948 res messages
                                      size  time | ratio min   max   std
                       http1     2,186,162  0.23 | 1.00  1.00  1.00  0.00
  delta2 (max_byte_size=256)       856,632 13.21 | 0.39  0.04  1.22  0.14
     headerdiff (buffer=256)     1,201,814  1.65 | 0.55  0.05  0.93  0.12

32 Byte Buffer
-------------------

* TOTAL: 5948 req messages
                                     size  time | ratio min   max   std
                      http1     3,460,925  0.20 | 1.00  1.00  1.00  0.00
  delta2 (max_byte_size=32)     2,357,457 28.18 | 0.68  0.51  0.84  0.05
     headerdiff (buffer=32)     2,791,039  1.16 | 0.81  0.58  0.96  0.08

* TOTAL: 5948 res messages
                                     size  time | ratio min   max   std
                      http1     2,186,162  0.21 | 1.00  1.00  1.00  0.00
  delta2 (max_byte_size=32)     1,197,019 17.92 | 0.55  0.16  0.89  0.07
     headerdiff (buffer=32)     1,434,721  1.32 | 0.66  0.19  0.95  0.07

[ smaller buffer sizes caused errors in delta2 (at least) ]

--
Mark Nottingham   http://www.mnot.net/
Received on Friday, 22 March 2013 06:32:54 GMT

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