Current File : //proc/self/root/usr/share/doc/systemtap-client-2.9/examples/lwtools/fsslower-nd.stp
#!/usr/bin/stap
/*
* fslower-nd.stp Trace slow file system sync reads and writes.
* For Linux, uses SystemTap (non-debuginfo).
*
* USAGE: ./fsslower-nd.stp [min_ms]
*
* This script uses kernel dynamic tracing of two common file system functions:
* do_sync_read() and do_sync_write(). This provides a view of just two file
* system request types. There are typically many others: asynchronous I/O,
* directory operations, file handle operations, etc, that this script does
* not instrument.
*
* By default, a minimum millisecond threshold of 10 is used.
*
* 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.
*
* 06-Feb-2015 Brendan Gregg Created this.
*/
global ts[65536]; # 65536 is max concurrent I/O
global sz[65536]; # "
global min_ms = 10;
probe begin
{
if (argv_1 != "") {
min_ms = strtol(argv_1, 10);
}
printf("Tracing FS sync reads and writes slower than %d ms...", min_ms);
printf(" Hit Ctrl-C to end.\n");
printf("%-8s %-6s %-16s %-14s %-7s %8s\n", "TIME", "PID", "COMM",
"FUNC", "SIZE", "LAT(ms)");
}
function hhmmss() {
return substr(ctime(gettimeofday_s()), 11, 8);
}
probe kprobe.function("do_sync_read"),
kprobe.function("do_sync_write")
{
sz[tid()] = int_arg(3);
ts[tid()] = gettimeofday_ns();
}
probe kprobe.function("sock_aio_write")
{
/* not a file system write */
sz[tid()] = 0;
ts[tid()] = 0;
}
probe kprobe.function("do_sync_read").return,
kprobe.function("do_sync_write").return
{
if (ts[tid()]) {
lat = (gettimeofday_ns() - ts[tid()]) / 1000000;
if (lat >= min_ms) {
printf("%-8s %-6d %-16s %-14s %-7d %8d\n", hhmmss(),
pid(), execname(), ppfunc(), sz[tid()], lat);
}
delete sz[tid()];
delete ts[tid()];
}
}
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