#!/bin/env stap

global devices, reads, writes

/* data collection: SCSI disk */
probe module("sd_mod").function("sd_init_command") ?, kernel.function("sd_init_command") ? {
  device=kernel_string($SCpnt->request->rq_disk->disk_name)
  sector_size=$SCpnt->device->sector_size
  nr_sectors=$SCpnt->request->nr_sectors
  devices[device] = 1
%(kernel_v>="2.6.19" %?
  if ($SCpnt->request->cmd_flags & 1)
%:
  if ($SCpnt->request->flags & 1)
%)
    writes[device] <<< nr_sectors * sector_size
  else
    reads[device] <<< nr_sectors * sector_size
}
/* data collection: SCSI tape */
probe module("st").function("st_do_scsi") ?, kernel.function("st_do_scsi") ? {
  device=kernel_string($STp->disk->disk_name)
  devices[device] = 1
  if ($direction)
    writes[device] <<< $bytes
  else
    reads[device] <<< $bytes
}


/* reporting */
global blksize=512
global hdrcount
probe timer.s($1) {
  if ((hdrcount++ % 10) == 0)
    printf("%9s %9s %9s %9s %9s %9s\n",
	   "Device:","tps","blk_read/s","blk_wrtn/s","blk_read","blk_wrtn")

  foreach (dev in devices) {
    rdcount=@count(reads[dev])
    wrcount=@count(writes[dev])
    tps=(rdcount+wrcount)*100/$1
    rdblkcount=rdcount ? @sum(reads[dev])/blksize : 0
    wrblkcount=wrcount ? @sum(writes[dev])/blksize : 0
    rdblkrate=rdblkcount*100/$1
    wrblkrate=wrblkcount*100/$1
    printf("%9s %6d.%02d %6d.%02d %6d.%02d %9d %9d\n",
	dev, tps/100,tps%100,
	rdblkrate/100,rdblkrate%100,
	wrblkrate/100,wrblkrate%100,
	rdblkcount, wrblkcount)
  }
  printf ("\n")
  delete devices
  delete reads
  delete writes
}