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#! /usr/bin/env stap
#
# Copyright (C) 2010 Red Hat, Inc.
# By Dominic Duval, Red Hat Inc.
# dduval@redhat.com
#
# Keeps track of seeks on devices.
# Shows how to use hist_log.
#
# USAGE: stap deviceseeks.stp
#
global seeks, oldsec
probe ioblock_trace.request {
if (size == 0) next
sectorsize = (@defined($q->limits->logical_block_size)
? $q->limits->logical_block_size
: (@defined($q->logical_block_size) ? $q->logical_block_size
: $q->hardsect_size))
# printf("%s %s\n", devname, rw ? "w" : "r")
sec = sector
seeks[devname] <<< sec - oldsec[devname]
oldsec[devname] = sector + (size/sectorsize)
}
probe end {
printf("\n")
foreach ([devname] in seeks- limit 5) {
printf("Device: %s\n", devname)
println(@hist_log(seeks[devname]))
}
}
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