#2886 NORM First D: some files shouldn't be compressed by jffs2

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#2886: some files shouldn't be compressed by jffs2
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  Reporter:  tomeu        |       Owner:  dwmw2                 
      Type:  enhancement  |      Status:  new                   
  Priority:  normal       |   Milestone:  First Deployment, V1.0
 Component:  kernel       |     Version:                        
Resolution:               |    Keywords:                        
  Verified:  0            |  
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Comment(by pascal):

 Maybe jffs2 should detect it all by it self.

 It is trivial to detect that a block didn't compress well, and then assume
 that the next equally sized block will not compress either and the just
 store the data. This will result in testing in the order of sqrt(filesize)
 bytes (is my math right?) to see if the file will compress, or 187KB in
 tests for the 35MB file. Increase the increment to 4 times and you need to
 compress something like 13KB to test the entire file.

 Perhaps you can use a fixed maximum block size after initially determining
 that it will not compress, so the detection of compressible data later in
 the stream does not suffer so badly.

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Ticket URL: <https://dev.laptop.org/ticket/2886#comment:3>
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