Review Board 2.0.15


Ruby: Change the access permissions for MOESI hammer

Review Request #984 - Created Jan. 10, 2012 and submitted

Information
Andreas Hansson
gem5
default
Reviewers
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Ruby: Change the access permissions for MOESI hammer

This patch changes the access permission for the WB_E_W state from
Busy to Read_Write to avoid having issues in follow-on patches with
functional accesses going through Ruby. This change was made after
consultation with all involved parties and is more of a work-around
than a fix.
util/regress all passing (disregarding t1000 and eio)
Ship it!
Nilay Vaish
Posted (Jan. 10, 2012, 2:01 a.m.)



  

   

   
    
    

   
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    It seems this patch causes the following regression to fail with a minor statsdiff:
build/ALPHA_SE_MOESI_hammer/tests/opt/quick/50.memtest/alpha/linux/memtest-ruby-MOESI_hammer FAILED!


Maximum error magnitude: +0.245398%

                                  Reference  New Value   Abs Diff   Pct Chg
Key statistics:

  host_mem_usage                     381740     376848      -4892    -1.28%
  sim_ticks                        19175808   19128751     -47057    -0.25%

Differences > 0%:

  sim_ticks                        19175808   19128751     -47057    -0.25%
  sim_seconds                      0.019176   0.019129  -0.000047    -0.25%
  system.cpu4.num_writes              53497      53534         37    +0.07%
  system.cpu3.num_writes              53686      53709         23    +0.04%
  system.cpu0.num_writes              53926      53947         21    +0.04%
  system.cpu5.num_reads               99742      99706        -36    -0.04%
  system.cpu4.num_reads               99524      99559         35    +0.04%
  system.cpu6.num_reads               99887      99859        -28    -0.03%
  system.cpu1.num_writes              53707      53693        -14    -0.03%
  system.cpu1.num_reads               98882      98903         21    +0.02%
  system.cpu7.num_reads               99347      99367         20    +0.02%
  system.cpu3.num_reads               99594      99611         17    +0.02%
  system.cpu6.num_writes              53292      53283         -9    -0.02%
  system.cpu2.num_reads               98977      98993         16    +0.02%
  system.cpu5.num_writes              53984      53981         -3    -0.01%
  system.cpu2.num_writes              53060      53059         -1    -0.00%
  system.cpu7.num_writes              53300      53299         -1    -0.00%

    
    
    
   
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    Nilay, Brad, 

Do the changes to the memtest-ruby-MOESI_hammer regression make sense?

    
    
    
   
    3. 


   
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    The functional reads and writes will probably happen more easily. So
this is expected.
    
    
    
   
    4.