#2278 BLOC Future : Memory pressure

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#2278: Memory pressure
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   Reporter:  cjb          |       Owner:  cjb           
       Type:  defect       |      Status:  new           
   Priority:  blocker      |   Milestone:  Future Release
  Component:  performance  |     Version:                
 Resolution:               |    Keywords:                
Next_action:  communicate  |    Verified:  0             
  Blockedby:               |    Blocking:                
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Comment(by thomaswamm):

 Replying to [comment:18 gnu]:
 > ... When a page is paged in from a shared library, the file system needs
 to uncompress it (this is not quick).  It is quickly thrown away due to
 memory pressure, and then needs to be re-read and re-uncompressed...

 I am curious if the uncompressing speed penalty is observable, perhaps by
 comparing jffs performance with ext3 performance.  A compressed file
 system is justifiable if mass storage is expensive. But maybe CPU cycles
 are even more expensive where electricity is scarce.  Flash memory is
 getting cheaper, but electricity is not.

 This ticket I presume is focussed on RAM memory pressure, but there are
 sure to be trade-offs with NAND capacity pressure and speed (performance)
 pressure.

 Maybe not compressing certain frequently-accessed files in jffs NAND would
 lead to measurable performance improvements?  Is it possible to control
 compression at the file level?

 P.S.:   I often don't know what I am talking about.  But sometimes I get
 lucky and say something useful.  I am no authority/expert.

-- 
Ticket URL: <http://dev.laptop.org/ticket/2278#comment:23>
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