iocost_monitor: Report debt

Report debt and rename del_ms row to delay for consistency.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-iocost.c

@@ -161,9 +161,9 @@
  * https://github.com/osandov/drgn.  The ouput looks like the following.
  *
  *  sdb RUN   per=300ms cur_per=234.218:v203.695 busy= +1 vrate= 62.12%
- *                 active      weight      hweight% inflt% del_ms usages%
- *  test/a              *    50/   50  33.33/ 33.33  27.65  0*041 033:033:033
- *  test/b              *   100/  100  66.67/ 66.67  17.56  0*000 066:079:077
+ *                 active      weight      hweight% inflt% dbt  delay usages%
+ *  test/a              *    50/   50  33.33/ 33.33  27.65   2  0*041 033:033:033
+ *  test/b              *   100/  100  66.67/ 66.67  17.56   0  0*000 066:079:077
  *
  * - per	: Timer period
  * - cur_per	: Internal wall and device vtime clock

tools/cgroup/iocost_monitor.py

@@ -135,7 +135,7 @@ class IocStat:
 
     def table_header_str(self):
         return f'{"":25} active {"weight":>9} {"hweight%":>13} {"inflt%":>6} ' \
-               f'{"del_ms":>6} {"usages%"}'
+               f'{"dbt":>3} {"delay":>6} {"usages%"}'
 
 class IocgStat:
     def __init__(self, iocg):
@@ -159,6 +159,7 @@ class IocgStat:
         else:
             self.inflight_pct = 0
 
+        self.debt_ms = iocg.abs_vdebt.counter.value_() / VTIME_PER_USEC / 1000
         self.use_delay = blkg.use_delay.counter.value_()
         self.delay_ms = blkg.delay_nsec.counter.value_() / 1_000_000
 
@@ -181,6 +182,7 @@ class IocgStat:
                 'hweight_active_pct'    : str(self.hwa_pct),
                 'hweight_inuse_pct'     : str(self.hwi_pct),
                 'inflight_pct'          : str(self.inflight_pct),
+                'debt_ms'               : str(self.debt_ms),
                 'use_delay'             : str(self.use_delay),
                 'delay_ms'              : str(self.delay_ms),
                 'usage_pct'             : str(self.usage),
@@ -195,6 +197,7 @@ class IocgStat:
               f'{self.inuse:5}/{self.active:5} ' \
               f'{self.hwi_pct:6.2f}/{self.hwa_pct:6.2f} ' \
               f'{self.inflight_pct:6.2f} ' \
+              f'{min(math.ceil(self.debt_ms), 999):3} ' \
               f'{min(self.use_delay, 99):2}*'\
               f'{min(math.ceil(self.delay_ms), 999):03} '
         for u in self.usages: