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Re: bohe implementation for compression tests

From: Roberto Peon <grmocg@gmail.com>
Date: Wed, 16 Jan 2013 17:09:01 -0800
Message-ID: <CAP+FsNeq4dFYErW-uv3LQ4wESYN90T4pD6mVM8G+_H76LcBcJw@mail.gmail.com>
To: Martin Thomson <martin.thomson@gmail.com>
Cc: James M Snell <jasnell@gmail.com>, "ietf-http-wg@w3.org" <ietf-http-wg@w3.org>
Unfortunately python does not lend itself to CPU consumption comparisons
(thus my writing the compressor in C++ the other day)
-=R


On Wed, Jan 16, 2013 at 5:06 PM, Martin Thomson <martin.thomson@gmail.com>wrote:

> James,
>
> Any feel for how bohe compares on CPU cost?  Ideally, the test harness
> would provide that information alongside the rest of the data.
>
> On 11 January 2013 10:43, James M Snell <jasnell@gmail.com> wrote:
> > Just continuing my investigation of various header compression strategies
> > around the BOHE mechanism. In my personal github fork, I have just
> checked
> > in two bohe variations, one that implements selective-compression, the
> other
> > implements isolated-compression..
> >
> > https://github.com/jasnell/compression-test/tree/master/compressor/bohe2
> > https://github.com/jasnell/compression-test/tree/master/compressor/bohe3
> >
> > With bohe2 (selective-compression), a header block can consist of a
> > compressed set of headers and an uncompressed set of headers. Specific
> > headers such as Cookie, Set-Cookie, etc can be marked as "Do Not
> Compress".
> > These are dropped into the frame as-is and thus avoid the CRIME issue
> > completely. The rest of the headers are compressed using gzip using the
> > existing spdy3 dictionary. Obviously this is not ideal because Cookie
> data
> > then is passed around without any compression at all, making it far less
> > efficient than any of the other options on the table.
> >
> > In bohe3 (isolated-compression), a header block can consist of two
> separate
> > compressed blocks generated using two separate stream compressor
> instances.
> > Selected headers (like Cookie) can be included in the secondary isolated
> > block which would never contain general user-provided header data.
> >
> > **These are only experiments right now and are not intended as serious
> > proposals for the spec**. Isolated-compression (bohe3) does show promise
> > however. If we can successfully isolate potentially sensitive headers
> into
> > their own compression context generated independently of any general
> > user-supplied data, we can effectively short-circuit the CRIME attack by
> > making it impossible for an attacker to compare values based on the
> > compression ratio... and since it still uses gzip compression, we
> achieve a
> > generally better compression ratio overall than we get with the proposed
> > delta encoding. For now, tho, just consider this all just to be fodder
> for
> > discussion. There are still MANY issues with these experimental
> approaches
> > and I still need to go through delta in more detail to see if there is a
> way
> > bohe and delta can be used effectively together.
> >
> > Just for example...
> >
> > james-snells-macbook-pro:compression-test james$
> ./compare_compressors.py -c
> > bohe3 -c bohe2 -c bohe -c delta -t
> > /Users/james/git/http_samples/mnot/amazon.com.har
> > 732 req messages processed
> >              compressed | ratio min   max   std
> > req  bohe        26,035 | 0.13  0.03  0.68  0.08
> > req bohe2        44,195 | 0.23  0.07  0.71  0.13
> > req bohe3        30,944 | 0.16  0.05  0.74  0.08
> > req delta        33,955 | 0.17  0.02  0.71  0.09
> > req http1       195,386 | 1.00  1.00  1.00  0.00
> >
> > 732 res messages processed
> >              compressed | ratio min   max   std
> > res  bohe        39,525 | 0.25  0.04  0.67  0.07
> > res bohe2        47,157 | 0.29  0.12  0.71  0.08
> > res bohe3        44,843 | 0.28  0.06  0.70  0.07
> > res delta        44,499 | 0.28  0.02  0.65  0.09
> > res http1       159,968 | 1.00  1.00  1.00  0.00
> >
> > - James
> >
> >
> >
> > On Thu, Jan 10, 2013 at 11:08 AM, James M Snell <jasnell@gmail.com>
> wrote:
> >>
> >> I have an initial bohe implementation for the compression tests... it's
> >> very preliminary and uses the same gzip compression as the current
> spdy3.
> >> I'm going to be playing around with the delta compression mechanism as
> well
> >> and see how much of an impact that has. Initial results are very
> promising
> >> but I haven't done much debugging yet. Just wanted folks to know that
> this
> >> work was underway...
> >>
> >> https://github.com/jasnell/compression-test/tree/master/compressor/bohe
> >>
> >> Some test runs....
> >>
> >> ./compare_compressors.py -c bohe -c spdy3 -c delta
> >> ../http_samples/mnot/amazon.com.har
> >> 732 req messages processed
> >>              compressed | ratio min   max   std
> >> req  bohe        26,122 | 0.13  0.04  0.70  0.08
> >> req delta        33,955 | 0.17  0.02  0.71  0.09
> >> req http1       195,386 | 1.00  1.00  1.00  0.00
> >> req spdy3        27,238 | 0.14  0.04  0.71  0.08
> >>
> >> 732 res messages processed
> >>              compressed | ratio min   max   std
> >> res  bohe        39,628 | 0.25  0.04  0.66  0.07
> >> res delta        44,499 | 0.28  0.02  0.65  0.09
> >> res http1       159,968 | 1.00  1.00  1.00  0.00
> >> res spdy3        41,325 | 0.26  0.04  0.67  0.08
> >>
> >>
> >> ./compare_compressors.py -c bohe -c spdy3 -c delta
> >> ../http_samples/mnot/craigslist.org.har
> >> 66 req messages processed
> >>              compressed | ratio min   max   std
> >> req  bohe         1,948 | 0.15  0.06  0.73  0.11
> >> req delta         2,036 | 0.16  0.07  0.71  0.11
> >> req http1        12,894 | 1.00  1.00  1.00  0.00
> >> req spdy3         2,016 | 0.16  0.07  0.75  0.11
> >>
> >> 66 res messages processed
> >>              compressed | ratio min   max   std
> >> res  bohe         1,786 | 0.18  0.07  0.77  0.13
> >> res delta         2,858 | 0.28  0.08  0.69  0.12
> >> res http1        10,147 | 1.00  1.00  1.00  0.00
> >> res spdy3         1,869 | 0.18  0.09  0.78  0.13
> >>
> >>
> >> ./compare_compressors.py -c bohe -c spdy3 -c delta
> >> ../http_samples/mnot/flickr.com.har
> >> 438 req messages processed
> >>              compressed | ratio min   max   std
> >> req  bohe        11,988 | 0.10  0.02  0.69  0.07
> >> req delta        26,372 | 0.22  0.01  0.71  0.14
> >> req http1       121,854 | 1.00  1.00  1.00  0.00
> >> req spdy3        12,550 | 0.10  0.02  0.71  0.07
> >>
> >> 438 res messages processed
> >>              compressed | ratio min   max   std
> >> res  bohe        13,073 | 0.09  0.05  0.66  0.06
> >> res delta        25,236 | 0.18  0.02  0.70  0.11
> >> res http1       140,457 | 1.00  1.00  1.00  0.00
> >> res spdy3        14,142 | 0.10  0.05  0.66  0.06
> >>
> >>
> >> ./compare_compressors.py -c bohe -c spdy3 -c delta
> >> ../http_samples/mnot/facebook.com.har
> >> 234 req messages processed
> >>              compressed | ratio min   max   std
> >> req  bohe         6,091 | 0.15  0.06  0.78  0.07
> >> req delta         7,800 | 0.19  0.02  0.70  0.07
> >> req http1        41,980 | 1.00  1.00  1.00  0.00
> >> req spdy3         6,301 | 0.15  0.06  0.77  0.07
> >>
> >> 234 res messages processed
> >>              compressed | ratio min   max   std
> >> res  bohe         9,458 | 0.23  0.07  0.68  0.07
> >> res delta        12,045 | 0.30  0.13  0.60  0.08
> >> res http1        40,252 | 1.00  1.00  1.00  0.00
> >> res spdy3         9,788 | 0.24  0.07  0.69  0.07
> >>
> >>
> >>
> >>
> >
>
>
Received on Thursday, 17 January 2013 01:09:29 GMT

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