Re: [Patch 2/2] blkiomon: I/O monitor

["Alan D. Brunelle" <Alan.Brunelle@hp.com>]

Martin Peschke wrote:
> blkiomon periodically generates per device request size and request latency
> statistics from blktrace data. It provides histograms as well as data that
> can be used to calculate min, max, average and variance. For this purpose,
> it consumes D and C traces read from stdin.
> 
> There are options for binary output and human-readable output to files and
> stdout. Output to a message queue is supported as well.
> 
> # blktrace /dev/sdw -a issue -a complete -w 3000 -o - \
>   | blkparse -i - -O -d - | blkiomon -I 10 -h -
> 
> device: 65,96   interval end: 1216044286134293


What units are 'interval end' displayed in?


> requests: read 521, write 34, bidir: 0
> sizes: min 4096, max 520192, sum 32059392, squ 4300285673472
> d2c: min 238, max 19274, sum 726186, squ 2428562090


Why not show the average? What is 'squ'?


> sizes histogram (in kB):
>        0       1       2       4       8      16      32      64
>      128     256     512    1024    2048    4096    8192   16384
>        0       0       0      64      17     144      71     117
>       97      42       3       0       0       0       0       0

These outputs are a bit hard to read - are they wrapped (from very, very
long lines), or is this how they are displayed? If the latter, why not
have some sort of MxN chart like:

   0:  0      1:  0      2:  0      4: 64
   8: 17     16:144     32: 71     64:117
 128: 97    256: 42    512:  3   1024:  0
2048:  0   4096:  0   8192:  0  16384:  0