#! stap
# Simple (dumb) script to figure out the sizes of IOs getting
# generated.
#
# TODO: 
#	- sort the output by iosizes for easy read
#	- add per device counters
#	- hook it up in right places (to handle failures correctly)
#

global iosizes

probe kernel.function("blk_rq_map_sg") {
   iosizes [$rq->nr_sectors] ++
}

function _(n) { return string(n) } 

function report () {
  foreach (io in iosizes) {
	if (iosizes[io])
		print("iosize  = " . _(io/2) .
		      "k\t iocount = " . _(iosizes[io]) .
		      "\n")
  }
  delete iosizes
}


probe begin {
  print ("io sizes tracking, start time=" . _(gettimeofday_s()) . "\n")
}
probe end {
  report()
  print ("io sizes tracking, end time=" . _(gettimeofday_s()) . "\n")
}