/usr/share/systemtap/examples/lwtools
Edit: /usr/share/systemtap/examples/lwtools/bitesize-nd.stp (1543B)
#!/usr/bin/stap
/*
* bitesize-nd.stp Measure storage (bio) I/O size distribution.
* For Linux, uses SystemTap (non-debuginfo).
*
* USAGE: ./bitesize-nd.stp
*
* This script uses the kernel tracepoint block_rq_insert. The output includes
* the name of the process or thread that was on-CPU when the I/O request was
* inserted on the issue queue.
*
* From systemtap-lwtools: https://github.com/brendangregg/systemtap-lwtools
*
* See the corresponding man page (in systemtap-lwtools) for more info.
*
* Copyright (C) 2015 Brendan Gregg.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* 01-Feb-2015 Brendan Gregg Created this.
*/
global sz;
probe begin
{
printf("Tracing block I/O... Hit Ctrl-C to end.\n");
}
probe kernel.trace("block_rq_insert") {
/*
* You aren't supposed to access __data_len directly as it is internal,
* but I don't see another way...
*/
sz[execname()] <<< $rq->__data_len;
}
probe end
{
printf("\nI/O size (bytes):\n\n");
foreach (name in sz+) {
printf("process name: %s\n", name);
print(@hist_log(sz[name]));
}
delete sz;
}