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#! /usr/bin/env stap
/*
* Copyright (C) 2006-2018 Red Hat Inc.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License v.2.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Print out the amount of time spent in the read and write systemcall
* when each file opened by the process is closed. Note that the systemtap
* script needs to be running before the open operations occur for
* the script to record data.
*
* This script could be used to to find out which files are slow to load
* on a machine. e.g.
*
* stap iotime.stp -c 'firefox'
*
* Output format is:
* timestamp pid (executabable) info_type path ...
*
* 200283135 2573 (cupsd) access /etc/printcap read: 0 write: 7063
* 200283143 2573 (cupsd) iotime /etc/printcap time: 69
*
*/
global start
global time_io
function timestamp:long() { return gettimeofday_us() - start }
function proc:string() { return sprintf("%d (%s)", pid(), execname()) }
probe begin { start = gettimeofday_us() }
global possible_filename, filehandles, fileread, filewrite
probe syscall.open, syscall.openat {
possible_filename[tid()] = filename
}
probe syscall.open.return, syscall.openat.return {
// Get filename even if non-dwarf syscall return probe are used.
filename = possible_filename[tid()]
delete possible_filename[tid()]
if (retval != -1) {
filehandles[pid(), retval] = filename
} else {
printf("%d %s access %s fail\n", timestamp(), proc(), filename)
}
}
global read_fds, write_fds
probe syscall.read { read_fds[tid()] = fd }
probe syscall.read.return {
p = pid()
// Get fd even if non-dwarf syscall return probe.
fd = read_fds[tid()]
delete read_fds[tid()]
bytes = retval
time = gettimeofday_us() - @entry(gettimeofday_us())
if (bytes > 0)
fileread[p, fd] <<< bytes
time_io[p, fd] <<< time
}
probe syscall.write { write_fds[tid()] = fd }
probe syscall.write.return {
p = pid()
// Get fd even if non-dwarf syscall return probe.
fd = write_fds[tid()]
delete write_fds[tid()]
bytes = retval
time = gettimeofday_us() - @entry(gettimeofday_us())
if (bytes > 0)
filewrite[p, fd] <<< bytes
time_io[p, fd] <<< time
}
probe syscall.close {
if ([pid(), fd] in filehandles) {
printf("%d %s access %s read: %d write: %d\n",
timestamp(), proc(), filehandles[pid(), fd],
@sum(fileread[pid(), fd]), @sum(filewrite[pid(), fd]))
if (@count(time_io[pid(), fd]))
printf("%d %s iotime %s time: %d\n", timestamp(), proc(),
filehandles[pid(), fd], @sum(time_io[pid(), fd]))
}
delete fileread[pid(), fd]
delete filewrite[pid(), fd]
delete filehandles[pid(), fd]
delete time_io[pid(),fd]
}
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