cardiff: Adding CPU analysis

This patch add the CPU analysis to compute :
- bogomips & loops_per_sec computation per host and per group
- an efficiency computation : all cores loaded at the same time vs all
  cores loaded one after the other.

A typical output looks like :
Group 2 : Checking CPU  perf
bogomips      : INFO    : logical_0  : Group performance : min= 3999.93, mean= 4000.12, max= 4000.26, stddev=    0.17
bogomips      : INFO    : logical_0  : Group performance = 4000.12   : CONSISTENT
bogomips      : INFO    : logical_1  : Group performance : min= 3999.87, mean= 3999.87, max= 3999.88, stddev=    0.01
bogomips      : INFO    : logical_1  : Group performance = 3999.87   : CONSISTENT
bogomips      : INFO    : logical_10 : Group performance : min= 3999.91, mean= 3999.96, max= 3999.99, stddev=    0.04
bogomips      : INFO    : logical_10 : Group performance = 3999.96   : CONSISTENT
bogomips      : INFO    : logical_11 : Group performance : min= 3999.96, mean= 3999.99, max= 4000.02, stddev=    0.03
bogomips      : INFO    : logical_11 : Group performance = 3999.99   : CONSISTENT
bogomips      : INFO    : logical_12 : Group performance : min= 4000.02, mean= 4000.03, max= 4000.05, stddev=    0.02
bogomips      : INFO    : logical_12 : Group performance = 4000.03   : CONSISTENT
bogomips      : INFO    : logical_13 : Group performance : min= 3999.92, mean= 3999.94, max= 3999.97, stddev=    0.03
bogomips      : INFO    : logical_13 : Group performance = 3999.94   : CONSISTENT
bogomips      : INFO    : logical_14 : Group performance : min= 3999.91, mean= 3999.94, max= 3999.97, stddev=    0.03
bogomips      : INFO    : logical_14 : Group performance = 3999.94   : CONSISTENT
bogomips      : INFO    : logical_15 : Group performance : min= 3999.96, mean= 3999.98, max= 4000.00, stddev=    0.02
bogomips      : INFO    : logical_15 : Group performance = 3999.98   : CONSISTENT
bogomips      : INFO    : logical_16 : Group performance : min= 3999.94, mean= 3999.95, max= 3999.95, stddev=    0.01
bogomips      : INFO    : logical_16 : Group performance = 3999.95   : CONSISTENT
bogomips      : INFO    : logical_17 : Group performance : min= 3999.94, mean= 3999.95, max= 3999.95, stddev=    0.01
bogomips      : INFO    : logical_17 : Group performance = 3999.95   : CONSISTENT
bogomips      : INFO    : logical_18 : Group performance : min= 3999.88, mean= 3999.93, max= 3999.96, stddev=    0.04
bogomips      : INFO    : logical_18 : Group performance = 3999.93   : CONSISTENT
bogomips      : INFO    : logical_19 : Group performance : min= 3999.89, mean= 3999.93, max= 3999.96, stddev=    0.04
bogomips      : INFO    : logical_19 : Group performance = 3999.93   : CONSISTENT
bogomips      : INFO    : logical_2  : Group performance : min= 3999.87, mean= 3999.88, max= 3999.88, stddev=    0.01
bogomips      : INFO    : logical_2  : Group performance = 3999.88   : CONSISTENT
bogomips      : INFO    : logical_20 : Group performance : min= 3999.92, mean= 3999.95, max= 3999.99, stddev=    0.04
bogomips      : INFO    : logical_20 : Group performance = 3999.95   : CONSISTENT
bogomips      : INFO    : logical_21 : Group performance : min= 3999.90, mean= 3999.94, max= 3999.96, stddev=    0.03
bogomips      : INFO    : logical_21 : Group performance = 3999.94   : CONSISTENT
bogomips      : INFO    : logical_22 : Group performance : min= 3999.93, mean= 3999.96, max= 3999.98, stddev=    0.03
bogomips      : INFO    : logical_22 : Group performance = 3999.96   : CONSISTENT
bogomips      : INFO    : logical_23 : Group performance : min= 3999.92, mean= 3999.94, max= 3999.96, stddev=    0.02
bogomips      : INFO    : logical_23 : Group performance = 3999.94   : CONSISTENT
bogomips      : INFO    : logical_24 : Group performance : min= 3999.94, mean= 3999.96, max= 3999.97, stddev=    0.02
bogomips      : INFO    : logical_24 : Group performance = 3999.96   : CONSISTENT
bogomips      : INFO    : logical_25 : Group performance : min= 3999.94, mean= 3999.95, max= 3999.96, stddev=    0.01
bogomips      : INFO    : logical_25 : Group performance = 3999.95   : CONSISTENT
bogomips      : INFO    : logical_26 : Group performance : min= 3999.95, mean= 3999.97, max= 4000.00, stddev=    0.03
bogomips      : INFO    : logical_26 : Group performance = 3999.97   : CONSISTENT
bogomips      : INFO    : logical_27 : Group performance : min= 3999.88, mean= 3999.94, max= 3999.99, stddev=    0.06
bogomips      : INFO    : logical_27 : Group performance = 3999.94   : CONSISTENT
bogomips      : INFO    : logical_28 : Group performance : min= 3999.95, mean= 3999.96, max= 3999.98, stddev=    0.02
bogomips      : INFO    : logical_28 : Group performance = 3999.96   : CONSISTENT
bogomips      : INFO    : logical_29 : Group performance : min= 3999.96, mean= 3999.97, max= 3999.99, stddev=    0.02
bogomips      : INFO    : logical_29 : Group performance = 3999.97   : CONSISTENT
bogomips      : INFO    : logical_3  : Group performance : min= 3999.86, mean= 3999.87, max= 3999.88, stddev=    0.01
bogomips      : INFO    : logical_3  : Group performance = 3999.87   : CONSISTENT
bogomips      : INFO    : logical_30 : Group performance : min= 3999.96, mean= 3999.96, max= 3999.96, stddev=    0.00
bogomips      : INFO    : logical_30 : Group performance = 3999.96   : CONSISTENT
bogomips      : INFO    : logical_31 : Group performance : min= 3999.97, mean= 4000.19, max= 4000.62, stddev=    0.37
bogomips      : INFO    : logical_31 : Group performance = 4000.19   : CONSISTENT
bogomips      : INFO    : logical_4  : Group performance : min= 3999.87, mean= 3999.88, max= 3999.89, stddev=    0.01
bogomips      : INFO    : logical_4  : Group performance = 3999.88   : CONSISTENT
bogomips      : INFO    : logical_5  : Group performance : min= 3999.88, mean= 3999.88, max= 3999.89, stddev=    0.01
bogomips      : INFO    : logical_5  : Group performance = 3999.88   : CONSISTENT
bogomips      : INFO    : logical_6  : Group performance : min= 3999.87, mean= 3999.88, max= 3999.90, stddev=    0.02
bogomips      : INFO    : logical_6  : Group performance = 3999.88   : CONSISTENT
bogomips      : INFO    : logical_7  : Group performance : min= 3999.87, mean= 3999.88, max= 3999.89, stddev=    0.01
bogomips      : INFO    : logical_7  : Group performance = 3999.88   : CONSISTENT
bogomips      : INFO    : logical_8  : Group performance : min= 3999.93, mean= 3999.95, max= 3999.97, stddev=    0.02
bogomips      : INFO    : logical_8  : Group performance = 3999.95   : CONSISTENT
bogomips      : INFO    : logical_9  : Group performance : min= 3999.90, mean= 3999.95, max= 3999.98, stddev=    0.04
bogomips      : INFO    : logical_9  : Group performance = 3999.95   : CONSISTENT
loops_per_sec : INFO    : logical_0  : Group performance : min=  452.00, mean=  456.67, max=  459.00, stddev=    4.04
loops_per_sec : INFO    : logical_0  : Group performance =  456.67   : CONSISTENT
loops_per_sec : INFO    : logical_1  : Group performance : min=  453.00, mean=  453.67, max=  454.00, stddev=    0.58
loops_per_sec : INFO    : logical_1  : Group performance =  453.67   : CONSISTENT
loops_per_sec : INFO    : logical_10 : Group performance : min=  451.00, mean=  451.33, max=  452.00, stddev=    0.58
loops_per_sec : INFO    : logical_10 : Group performance =  451.33   : CONSISTENT
loops_per_sec : INFO    : logical_11 : Group performance : min=  452.00, mean=  452.33, max=  453.00, stddev=    0.58
loops_per_sec : INFO    : logical_11 : Group performance =  452.33   : CONSISTENT
loops_per_sec : INFO    : logical_12 : Group performance : min=  452.00, mean=  452.67, max=  454.00, stddev=    1.15
loops_per_sec : INFO    : logical_12 : Group performance =  452.67   : CONSISTENT
loops_per_sec : INFO    : logical_13 : Group performance : min=  453.00, mean=  453.33, max=  454.00, stddev=    0.58
loops_per_sec : INFO    : logical_13 : Group performance =  453.33   : CONSISTENT
loops_per_sec : INFO    : logical_14 : Group performance : min=  453.00, mean=  453.67, max=  454.00, stddev=    0.58
loops_per_sec : INFO    : logical_14 : Group performance =  453.67   : CONSISTENT
loops_per_sec : INFO    : logical_15 : Group performance : min=  454.00, mean=  455.00, max=  457.00, stddev=    1.73
loops_per_sec : INFO    : logical_15 : Group performance =  455.00   : CONSISTENT
loops_per_sec : INFO    : logical_16 : Group performance : min=  453.00, mean=  454.67, max=  456.00, stddev=    1.53
loops_per_sec : INFO    : logical_16 : Group performance =  454.67   : CONSISTENT
loops_per_sec : INFO    : logical_17 : Group performance : min=  449.00, mean=  453.67, max=  457.00, stddev=    4.16
loops_per_sec : INFO    : logical_17 : Group performance =  453.67   : CONSISTENT
loops_per_sec : INFO    : logical_18 : Group performance : min=  449.00, mean=  454.00, max=  457.00, stddev=    4.36
loops_per_sec : INFO    : logical_18 : Group performance =  454.00   : CONSISTENT
loops_per_sec : INFO    : logical_19 : Group performance : min=  449.00, mean=  452.67, max=  458.00, stddev=    4.73
loops_per_sec : INFO    : logical_19 : Group performance =  452.67   : CONSISTENT
loops_per_sec : INFO    : logical_2  : Group performance : min=  454.00, mean=  454.33, max=  455.00, stddev=    0.58
loops_per_sec : INFO    : logical_2  : Group performance =  454.33   : CONSISTENT
loops_per_sec : INFO    : logical_20 : Group performance : min=  450.00, mean=  450.00, max=  450.00, stddev=    0.00
loops_per_sec : INFO    : logical_20 : Group performance =  450.00   : CONSISTENT
loops_per_sec : INFO    : logical_21 : Group performance : min=  451.00, mean=  451.33, max=  452.00, stddev=    0.58
loops_per_sec : INFO    : logical_21 : Group performance =  451.33   : CONSISTENT
loops_per_sec : INFO    : logical_22 : Group performance : min=  452.00, mean=  452.33, max=  453.00, stddev=    0.58
loops_per_sec : INFO    : logical_22 : Group performance =  452.33   : CONSISTENT
loops_per_sec : INFO    : logical_23 : Group performance : min=  452.00, mean=  453.00, max=  454.00, stddev=    1.00
loops_per_sec : INFO    : logical_23 : Group performance =  453.00   : CONSISTENT
loops_per_sec : INFO    : logical_24 : Group performance : min=  454.00, mean=  459.33, max=  462.00, stddev=    4.62
loops_per_sec : INFO    : logical_24 : Group performance =  459.33   : CONSISTENT
loops_per_sec : INFO    : logical_25 : Group performance : min=  454.00, mean=  454.33, max=  455.00, stddev=    0.58
loops_per_sec : INFO    : logical_25 : Group performance =  454.33   : CONSISTENT
loops_per_sec : INFO    : logical_26 : Group performance : min=  454.00, mean=  455.00, max=  457.00, stddev=    1.73
loops_per_sec : INFO    : logical_26 : Group performance =  455.00   : CONSISTENT
loops_per_sec : INFO    : logical_27 : Group performance : min=  455.00, mean=  456.00, max=  458.00, stddev=    1.73
loops_per_sec : INFO    : logical_27 : Group performance =  456.00   : CONSISTENT
loops_per_sec : INFO    : logical_28 : Group performance : min=  449.00, mean=  454.00, max=  457.00, stddev=    4.36
loops_per_sec : INFO    : logical_28 : Group performance =  454.00   : CONSISTENT
loops_per_sec : INFO    : logical_29 : Group performance : min=  449.00, mean=  452.67, max=  458.00, stddev=    4.73
loops_per_sec : INFO    : logical_29 : Group performance =  452.67   : CONSISTENT
loops_per_sec : INFO    : logical_3  : Group performance : min=  454.00, mean=  454.67, max=  455.00, stddev=    0.58
loops_per_sec : INFO    : logical_3  : Group performance =  454.67   : CONSISTENT
loops_per_sec : INFO    : logical_30 : Group performance : min=  450.00, mean=  450.67, max=  452.00, stddev=    1.15
loops_per_sec : INFO    : logical_30 : Group performance =  450.67   : CONSISTENT
loops_per_sec : INFO    : logical_31 : Group performance : min=  451.00, mean=  451.67, max=  453.00, stddev=    1.15
loops_per_sec : INFO    : logical_31 : Group performance =  451.67   : CONSISTENT
loops_per_sec : INFO    : logical_4  : Group performance : min=  455.00, mean=  455.33, max=  456.00, stddev=    0.58
loops_per_sec : INFO    : logical_4  : Group performance =  455.33   : CONSISTENT
loops_per_sec : INFO    : logical_5  : Group performance : min=  455.00, mean=  456.33, max=  458.00, stddev=    1.53
loops_per_sec : INFO    : logical_5  : Group performance =  456.33   : CONSISTENT
loops_per_sec : INFO    : logical_6  : Group performance : min=  449.00, mean=  454.00, max=  457.00, stddev=    4.36
loops_per_sec : INFO    : logical_6  : Group performance =  454.00   : CONSISTENT
loops_per_sec : INFO    : logical_7  : Group performance : min=  450.00, mean=  455.00, max=  458.00, stddev=    4.36
loops_per_sec : INFO    : logical_7  : Group performance =  455.00   : CONSISTENT
loops_per_sec : INFO    : logical_8  : Group performance : min=  457.00, mean=  457.67, max=  459.00, stddev=    1.15
loops_per_sec : INFO    : logical_8  : Group performance =  457.67   : CONSISTENT
loops_per_sec : INFO    : logical_9  : Group performance : min=  450.00, mean=  450.33, max=  451.00, stddev=    0.58
loops_per_sec : INFO    : logical_9  : Group performance =  450.33   : CONSISTENT
loops_per_sec : INFO    : CPU Effi.  : Group performance =   75.73 % : CONSISTENT