#!/usr/bin/env stap 
#
# Copyright (C) 2007 Oracle Corp.
#
# Get the status of reading/writing disk every 5 seconds, output top ten entries 
#
# This is free software,GNU General Public License (GPL); either version 2, or (at your option) any
# later version.
#
# Usage:
#  ./disktop.stp
#

global io_stat,device
global read_bytes,write_bytes

probe kernel.function("vfs_read").return {
	if ($return>0) {
		dev = __file_dev($file)
		devname = __find_bdevname(dev,__file_bdev($file))

		if (devname!="N/A") {/*skip read from cache*/
			io_stat[pid(),execname(),uid(),ppid(),"R"] += $return
			device[pid(),execname(),uid(),ppid(),"R"] = devname
			read_bytes += $return
		}
	}
}

probe kernel.function("vfs_write").return {
	if ($return>0) {
		dev = __file_dev($file)
		devname = __find_bdevname(dev,__file_bdev($file))

		if (devname!="N/A") { /*skip update cache*/
			io_stat[pid(),execname(),uid(),ppid(),"W"] += $return
			device[pid(),execname(),uid(),ppid(),"W"] = devname
			write_bytes += $return
		}
	}
}

probe timer.ms(5000) {
	/* skip non-read/write disk */
	if (read_bytes+write+bytes) {

		printf("\n%-25s, %-8s%4dKb/sec, %-7s%6dKb, %-7s%6dKb\n\n",ctime(gettimeofday_s()),"Average:",
      		((read_bytes+write_bytes)/1024)/5,"Read:",read_bytes/1024,"Write:",write_bytes/1024)

		/* print header */
		printf("%8s %8s %8s %25s %8s %4s %12s\n","UID","PID","PPID","CMD","DEVICE","T","BYTES")
	}
	/* print top ten I/O */
	foreach ([process,cmd,userid,parent,action] in io_stat- limit 10)
	  printf("%8d %8d %8d %25s %8s %4s %12d\n",userid,process,parent,cmd,device[process,cmd,userid,parent,action],action,io_stat[process,cmd,userid,parent,action])

	/* clear data */
	delete io_stat
	delete device
	read_bytes = 0
	write_bytes = 0	
}

probe end{
	delete io_stat
	delete device
	delete read_bytes
	delete write_bytes	
}