tools/vfscount

#!/usr/bin/python
#
# vfscount	Count VFS calls ("vfs_*").
#		For Linux, uses BCC, eBPF. See .c file.
#
# Written as a basic example of counting functions.
#
# Copyright (c) 2015 Brendan Gregg.
# Licensed under the Apache License, Version 2.0 (the "License")
#
# 14-Aug-2015	Brendan Gregg	Created this.

from __future__ import print_function
from bpf import BPF
from ctypes import c_ushort, c_int, c_ulonglong
from time import sleep, strftime
from sys import stderr

# kernel symbol translation
ksym_addrs = []			# addresses for binary search
ksym_names = []			# same index as ksym_addrs
def load_kallsyms():
	symfile = "/proc/kallsyms"
	try:
		syms = open(symfile, "r")
	except:
		print("ERROR: reading " + symfile, file=sys.stderr)
		exit()
	line = syms.readline()
	for line in iter(syms):
		cols = line.split()
		name = cols[2]
		if name[:4] != "vfs_":	# perf optimization
			continue
		addr = int(cols[0], 16)
		ksym_addrs.append(addr)
		ksym_names.append(name)
	syms.close()
def _ksym_addr2index(addr):
	start = -1
	end = len(ksym_addrs)
	while end != start + 1:
		mid = int((start + end) / 2)
		if addr < ksym_addrs[mid]:
			end = mid
		else:
			start = mid
	return start
def ksym(addr):
	idx = _ksym_addr2index(addr)
	if idx == -1:
		return "[unknown]"
	return ksym_names[idx]
load_kallsyms()

# load BPF program
b = BPF(src_file = "vfscount.c")
b.attach_kprobe(event_re="^vfs_.*", fn_name="do_count")

# header
print("Tracing... Ctrl-C to end.")

# output
try:
	sleep(99999999)
except KeyboardInterrupt:
	pass

print("\n%-16s %-26s %8s" % ("ADDR", "FUNC", "COUNT"))
counts = b.get_table("counts")
for k, v in sorted(counts.items(), key=lambda counts: counts[1].value):
	print("%-16x %-26s %8d" % (k.ip, ksym(k.ip), v.value))