Re: [Aiod-users] [PATCH] Calculate latency standard deviation in aiod

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Joshua Root wrote:
> This patch makes aiod calculate and display the standard deviation of 
> the latencies when using the -l option. Knuth's algorithm is used, and 
> since it also needs to calculate the mean, a_lat() is no longer needed.
Hi Josh -

I reformatted the output a little:

$ sudo aiod -A 16 -D -b 128k -F 100g-f /dev/squat00 -I -i 1 -l -R -s 
nullrb -v -f /dev/squat01
   19.0935:    1600812 IOs   10480.10 MB/sec (5240.05 MB/sec/file)  97.7%

AIOD completed 1 iterations successfully
    Elapsed time :    19.4083sec    (0.076005 u + 67.764235 s)
    Total IOs    :    1638400    IOs/file         :     819200
    Total MB     :  204800.00    Total MB/file    :  102400.00
    IOs/sec      :   84417.47    IOs/file/sec     :   42208.73
    Total MB/sec :   10552.18    Total MB/sec/file:    5276.09
    # submits    :     108673    IOs out / submit :      15.08
    # reclaims   :     108673    IOs out / reclaim:      16.00
    IOs / reclaim:       15.1

Latencies for         TOTAL    squat01    squat00
      < 0.001 sec     93.39%     94.93%     91.84%
0.001 - 0.002 sec      6.60%      5.04%      8.15%
0.003 - 0.004 sec      0.01%      0.01%      0.01%
0.005 - 0.009 sec      0.01%      0.01%      0.00%
0.010 - 0.019 sec      0.01%      0.01%      0.00%
0.020 - 0.049 sec      0.00%      0.00%      0.00%
0.050 - 0.099 sec      0.00%      0.00%      0.00%
0.100 - 0.249 sec      0.00%      0.00%      0.00%
0.250 - 0.499 sec      0.00%      0.00%      0.00%
0.500 - 0.749 sec      0.00%      0.00%      0.00%
0.750 - 0.999 sec      0.00%      0.00%      0.00%
1.000 - 2.000 sec      0.00%      0.00%      0.00%
      > 2.000 sec      0.00%      0.00%      0.00%

Avg Latency (sec)  0.00006788 0.00005288 0.00008290

Standard Deviation 0.00026508 0.00024758 0.00028073

Per file               squat01    squat00
      (MB / second)    5375.61    5276.45
     (runtime secs)      19.05      19.41

And put in a check to make sure there was some data, but the patch looks 
good, and I've updated the CVS repository with this.

Thanks,
Alan