简述

funccount对事件，特别是函数调用进行计数，可以使它获取

• 某个内核态或用户态函数是否被调用过
• 该函数每秒被调用多少次

funccount在内核中使用一个BPF映射表数据结构维护事件计数，它只讲总数给用户态。

语法

funccoount的命令行参数包括可以用来改变的选型和事件字符串：

funccount [options] eventname

eventname的语法是：

• name或p:name：对内核函数name()进行插装。
• lib:name或p:lib:name：对用户态lib库中的函数name进行插桩。
• path:name：对于path路径下文件的用户态函数name进行插桩。
• t:system:name：对名为system:name的内核跟踪点进行插装。
• u:lib:name：对lib库中名为name的USDT探针进行插桩。
• *：用来匹配任意字符的通配符。

选项：

• -h、–help：显示帮助信息
• -p PID、–pid PID：只对该PID进行跟踪
• -i INTERVAL、–interval INTERVAL：统计总数，每INTERVAL秒
• -d DURATION、–duration DURATION：总共跟踪的秒数
• -T、–timestamp：输出时间
• -r、–regexp：使用正则表达式
• -D、–debug：启动前打印BPF程序信息

示例

对虚拟文件系统(VFS)内核函数进行统计：

funccount-bpfcc 'vfs_*'

对TCP内核函数进行计数：

funccount-bpfcc 'tcp_*'

统计每秒TCP发送函数的调用次数：

funccount-bpfcc -i 1 'tcp_send*'

统计每秒块I/O时间的数量：

funccount-bpfcc -i 1 't:block:*'

展示每秒新创建的进程数量：

funccount-bpfcc -i 1 t:sched:sched_process_fork

展示每秒libc中的getaddrinfo函数的调用次数：

funccount-bpfcc -i c:getaddrinfo

对libgo中全部的os.*调用进行计数：

funccount-bpfcc 'go:os.*'

源码

#!/usr/bin/python# @lint-avoid-python-3-compatibility-imports## funccount Count functions, tracepoints, and USDT probes.#    For Linux, uses BCC, eBPF.## USAGE: funccount [-h] [-p PID] [-i INTERVAL] [-d DURATION] [-T] [-r]#    [-c CPU] pattern## The pattern is a string with optional '*' wildcards, similar to file# globbing. If you'd prefer to use regular expressions, use the -r option.## Copyright (c) 2015 Brendan Gregg.# Licensed under the Apache License, Version 2.0 (the "License")## 09-Sep-2015   Brendan GreggCreated this.# 18-Oct-2016   Sasha Goldshtein    Generalized for uprobes, tracepoints, USDT.from __future__ import print_functionfrom bcc import ArgString, BPF, USDTfrom time import sleep, strftimeimport argparseimport reimport signalimport sysimport tracebackdebug = Falsedef verify_limit(num):    probe_limit = BPF.get_probe_limit()    if num > probe_limit: raise Exception("maximum of %d probes allowed, attempted %d" %   (probe_limit, num))class Probe(object):    def __init__(self, pattern, use_regex=False, pid=None, cpu=None): """Init a new probe. Init the probe from the pattern provided by the user. The supported patterns mimic the 'trace' and 'argdist' tools, but are simpler because we don't have to distinguish between probes and retprobes.     func     -- probe a kernel function     lib:func -- probe a user-space function in the library 'lib'     /path:func      -- probe a user-space function in binary '/path'     p::func  -- same thing as 'func'     p:lib:func      -- same thing as 'lib:func'     t:cat:event     -- probe a kernel tracepoint     u:lib:probe     -- probe a USDT tracepoint """ parts = bytes(pattern).split(b':') if len(parts) == 1:     parts = [b"p", b"", parts[0]] elif len(parts) == 2:     parts = [b"p", parts[0], parts[1]] elif len(parts) == 3:     if parts[0] == b"t":  parts = [b"t", b"", b"%s:%s" % tuple(parts[1:])]     if parts[0] not in [b"p", b"t", b"u"]:  raise Exception("Type must be 'p', 't', or 'u', but got %s" %    parts[0]) else:     raise Exception("Too many ':'-separated components in pattern %s" %pattern) (self.type, self.library, self.pattern) = parts if not use_regex:     self.pattern = self.pattern.replace(b'*', b'.*')     self.pattern = b'^' + self.pattern + b'$' if (self.type == b"p" and self.library) or self.type == b"u":     libpath = BPF.find_library(self.library)     if libpath is None:  # This might be an executable (e.g. 'bash')  libpath = BPF.find_exe(str(self.library))     if libpath is None or len(libpath) == 0:  raise Exception("unable to find library %s" % self.library)     self.library = libpath self.pid = pid self.cpu = cpu self.matched = 0 self.trace_functions = {}   # map location number to function name    def is_kernel_probe(self): return self.type == b"t" or (self.type == b"p" and self.library == b"")# 加载到内核    def attach(self): if self.type == b"p" and not self.library:     for index, function in self.trace_functions.items():  self.bpf.attach_kprobe(   event=function,   fn_name="trace_count_%d" % index) elif self.type == b"p" and self.library:     for index, function in self.trace_functions.items():  self.bpf.attach_uprobe(   name=self.library,   sym=function,   fn_name="trace_count_%d" % index,   pid=self.pid or -1) elif self.type == b"t":     for index, function in self.trace_functions.items():  self.bpf.attach_tracepoint(   tp=function,   fn_name="trace_count_%d" % index) elif self.type == b"u":     pass    # Nothing to do -- attach already happened in `load`    def _add_function(self, template, probe_name): new_func = b"trace_count_%d" % self.matched text = template.replace(b"PROBE_FUNCTION", new_func) text = text.replace(b"LOCATION", b"%d" % self.matched) self.trace_functions[self.matched] = probe_name self.matched += 1 return text    def _generate_functions(self, template): self.usdt = None text = b"" if self.type == b"p" and not self.library:     functions = BPF.get_kprobe_functions(self.pattern)     verify_limit(len(functions))     for function in functions:  text += self._add_function(template, function) elif self.type == b"p" and self.library:     # uprobes are tricky because the same function may have multiple     # addresses, and the same address may be mapped to multiple     # functions. We aren't allowed to create more than one uprobe     # per address, so track unique addresses and ignore functions that     # map to an address that we've already seen. Also ignore functions     # that may repeat multiple times with different addresses.     addresses, functions = (set(), set())     functions_and_addresses = BPF.get_user_functions_and_addresses(     self.library, self.pattern)     verify_limit(len(functions_and_addresses))     for function, address in functions_and_addresses:  if address in addresses or function in functions:      continue  addresses.add(address)  functions.add(function)  text += self._add_function(template, function) elif self.type == b"t":     tracepoints = BPF.get_tracepoints(self.pattern)     verify_limit(len(tracepoints))     for tracepoint in tracepoints:  text += self._add_function(template, tracepoint) elif self.type == b"u":     self.usdt = USDT(path=str(self.library), pid=self.pid)     matches = []     for probe in self.usdt.enumerate_probes():  if not self.pid and (probe.bin_path != self.library):      continue  if re.match(self.pattern, probe.name):      matches.append(probe.name)     verify_limit(len(matches))     for match in matches:  new_func = b"trace_count_%d" % self.matched  text += self._add_function(template, match)  self.usdt.enable_probe(match, new_func)     if debug:  print(self.usdt.get_text()) return text    def load(self): trace_count_text = b"""int PROBE_FUNCTION(void *ctx) {    FILTERPID    FILTERCPU    int loc = LOCATION;    counts.atomic_increment(loc);    return 0;} """ bpf_text = b"""#include BPF_ARRAY(counts, u64, NUMLOCATIONS); """ # We really mean the tgid from the kernel's perspective, which is in # the top 32 bits of bpf_get_current_pid_tgid(). if self.pid:     trace_count_text = trace_count_text.replace(b'FILTERPID',  b"""u32 pid = bpf_get_current_pid_tgid() >> 32;     if (pid != %d) { return 0; }""" % self.pid) else:     trace_count_text = trace_count_text.replace(b'FILTERPID', b'') if self.cpu:     trace_count_text = trace_count_text.replace(b'FILTERCPU',  b"""u32 cpu = bpf_get_smp_processor_id();     if (cpu != %d) { return 0; }""" % int(self.cpu)) else:     trace_count_text = trace_count_text.replace(b'FILTERCPU', b'') bpf_text += self._generate_functions(trace_count_text) bpf_text = bpf_text.replace(b"NUMLOCATIONS", b"%d" % len(self.trace_functions)) if debug:     print(bpf_text) if self.matched == 0:     raise Exception("No functions matched by pattern %s" %self.pattern) self.bpf = BPF(text=bpf_text,  usdt_contexts=[self.usdt] if self.usdt else []) self.clear()    # Initialize all array items to zero    def counts(self): return self.bpf["counts"]    def clear(self): counts = self.bpf["counts"] for location, _ in list(self.trace_functions.items()):     counts[counts.Key(location)] = counts.Leaf()class Tool(object):    def __init__(self): examples = """examples:    ./funccount 'vfs_*'      # count kernel fns starting with "vfs"    ./funccount -r '^vfs.*'  # same as above, using regular expressions    ./funccount -Ti 5 'vfs_*'# output every 5 seconds, with timestamps    ./funccount -d 10 'vfs_*'# trace for 10 seconds only    ./funccount -p 185 'vfs_*'      # count vfs calls for PID 181 only    ./funccount t:sched:sched_fork  # count calls to the sched_fork tracepoint    ./funccount -p 185 u:node:gc*   # count all GC USDT probes in node, PID 185    ./funccount c:malloc     # count all malloc() calls in libc    ./funccount go:os.*      # count all "os.*" calls in libgo    ./funccount -p 185 go:os.*      # count all "os.*" calls in libgo, PID 185    ./funccount ./test:read* # count "read*" calls in the ./test binary    ./funccount -c 1 'vfs_*' # count vfs calls on CPU 1 only    """ parser = argparse.ArgumentParser(     description="Count functions, tracepoints, and USDT probes",     formatter_class=argparse.RawDescriptionHelpFormatter,     epilog=examples) parser.add_argument("-p", "--pid", type=int,     help="trace this PID only") parser.add_argument("-i", "--interval",     help="summary interval, seconds") parser.add_argument("-d", "--duration",     help="total duration of trace, seconds") parser.add_argument("-T", "--timestamp", action="store_true",     help="include timestamp on output") parser.add_argument("-r", "--regexp", action="store_true",     help="use regular expressions. Default is \"*\" wildcards only.") parser.add_argument("-D", "--debug", action="store_true",     help="print BPF program before starting (for debugging purposes)") parser.add_argument("-c", "--cpu",     help="trace this CPU only") parser.add_argument("pattern",     type=ArgString,     help="search expression for events") self.args = parser.parse_args() global debug debug = self.args.debug self.probe = Probe(self.args.pattern, self.args.regexp, self.args.pid,      self.args.cpu) if self.args.duration and not self.args.interval:     self.args.interval = self.args.duration if not self.args.interval:     self.args.interval = 99999999    @staticmethod    def _signal_ignore(signal, frame): print()    def run(self): # 加载BPF程序 self.probe.load() self.probe.attach() print("Tracing %d functions for \"%s\"... Hit Ctrl-C to end." %(self.probe.matched, bytes(self.args.pattern))) exiting = 0 if self.args.interval else 1 seconds = 0 while True:     try:  sleep(int(self.args.interval))  seconds += int(self.args.interval)     except KeyboardInterrupt:  exiting = 1  # as cleanup can take many seconds, trap Ctrl-C:  signal.signal(signal.SIGINT, Tool._signal_ignore)     if self.args.duration and seconds >= int(self.args.duration):  exiting = 1     print()     if self.args.timestamp:  print("%-8s\n" % strftime("%H:%M:%S"), end="")     print("%-36s %8s" % ("FUNC", "COUNT"))     counts = self.probe.counts()     for k, v in sorted(counts.items(),   key=lambda counts: counts[1].value):  if v.value == 0:      continue  print("%-36s %8d" % (self.probe.trace_functions[k.value], v.value))     if exiting:  print("Detaching...")  exit()     else:  self.probe.clear()if __name__ == "__main__":    try: Tool().run()    except Exception: if debug:     traceback.print_exc() elif sys.exc_info()[0] is not SystemExit:     print(sys.exc_info()[1])

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