blob: bd16dd501ceab5a8f9744744e6257e2be23fd460 [file] [log] [blame]
#!/usr/bin/python
#
# vfsreadlat.py VFS read latency distribution.
# For Linux, uses BCC, eBPF. See .c file.
#
# Written as a basic example of a function latency distribution histogram.
#
# USAGE: vfsreadlat.py [interval [count]]
#
# The default interval is 5 seconds. A Ctrl-C will print the partially
# gathered histogram then exit.
#
# Copyright (c) 2015 Brendan Gregg.
# Licensed under the Apache License, Version 2.0 (the "License")
#
# 15-Aug-2015 Brendan Gregg Created this.
from bcc import BPF
from ctypes import c_ushort, c_int, c_ulonglong
from time import sleep
from sys import argv
def usage():
print("USAGE: %s [interval [count]]" % argv[0])
exit()
# arguments
interval = 5
count = -1
if len(argv) > 1:
try:
interval = int(argv[1])
if interval == 0:
raise
if len(argv) > 2:
count = int(argv[2])
except: # also catches -h, --help
usage()
# load BPF program
b = BPF(src_file = "vfsreadlat.c")
b.attach_kprobe(event="vfs_read", fn_name="do_entry")
b.attach_kretprobe(event="vfs_read", fn_name="do_return")
# header
print("Tracing... Hit Ctrl-C to end.")
# output
loop = 0
do_exit = 0
while (1):
if count > 0:
loop += 1
if loop > count:
exit()
try:
sleep(interval)
except KeyboardInterrupt:
pass; do_exit = 1
print
b["dist"].print_log2_hist("usecs")
b["dist"].clear()
if do_exit:
exit()