[PATCH] Take 2: Support to display stats from slave devices of a software RAID device

Hi Jens

This patch also includes the inward-indentation support for slave
device stat line. See the new lines in show_disk_util() function.

I'll see what incorporating dm support entails.

In the next few days, I'll send another patch that aggregates the
slave stats into the fields which are unavailable for the master device.

-Shehjar

raisin:/usr/local/shehjart/gitsources/fio# ./fio test
job1: (g=0): rw=read, bs=16M-16M/16M-16M, ioengine=sync, iodepth=1
Starting 1 process
Jobs: 1 (f=1): [R] [100.0% done] [360800/ 0 kb/s] [eta 00m:00s]
job1: (groupid=0, jobs=1): err= 0: pid=6253
  read : io=2048MiB, bw=340762KiB/s, iops=20, runt= 6302msec
    clat (msec): min=42, max=216, avg=49.23, stdev=18.11
    bw (KiB/s) : min=195083, max=379861, per=99.25%, avg=338216.73, stdev=53401.00
  cpu : usr=0.00%, sys=2.60%, ctx=129, majf=0, minf=1031
  IO depths : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
     submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued r/w: total=128/0, short=0/0

     lat (msec): 50=84.38%, 100=14.06%, 250=1.56%

Run status group 0 (all jobs):
   READ: io=2048MiB, aggrb=340762KiB/s, minb=340762KiB/s, maxb=340762KiB/s, mint=6302msec, maxt=6302msec

Disk stats (read/write):
  md0: ios=32768/0, merge=0/0, ticks=0/0, in_queue=0, util=0.00%
    sdc: ios=6554/0, merge=0/0, ticks=142096/0, in_queue=142092, util=86.46%
    sdd: ios=6554/0, merge=0/0, ticks=144712/0, in_queue=144712, util=86.98%
    sdf: ios=6554/0, merge=0/0, ticks=140556/0, in_queue=140552, util=85.74%
    sdg: ios=6553/0, merge=0/0, ticks=117220/0, in_queue=117216, util=75.57%
    sdt: ios=6553/0, merge=0/0, ticks=105984/0, in_queue=105984, util=68.30%
raisin:/usr/local/shehjart/gitsources/fio#