#!/usr/bin/stap
/*
* rwtime-nd.stp read/write syscalls by latency.
* For Linux, uses SystemTap (non-debuginfo).
*
* USAGE: ./rwtime.stp [execname]
*
* An option argument of the program name, eg, "httpd", can be provided. Without
* this, all processes are traced.
*
* 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.
*
* 24-Jun-2014 Brendan Gregg Created this.
*/
global read, write, tproc = "";
probe begin
{
tproc = argv_1;
if (tproc != "") {
printf("Tracing read/write syscalls for processes named \"%s\"",
tproc);
} else {
printf("Tracing read/write syscalls");
}
printf("... Hit Ctrl-C to end.\n");
}
probe nd_syscall.read.return
{
if (tproc == "" || execname() == tproc) {
read <<< gettimeofday_ns() - @entry(gettimeofday_ns());
}
}
probe nd_syscall.write.return
{
if (tproc == "" || execname() == tproc) {
write <<< gettimeofday_ns() - @entry(gettimeofday_ns());
}
}
probe end
{
printf("\nsyscall read latency (ns):\n");
if (@count(read)) { print(@hist_log(read)); }
printf("syscall write latency (ns):\n");
if (@count(write)) { print(@hist_log(write)); }
}
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