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#!/usr/bin/python
# @lint-avoid-python-3-compatibility-imports
#
# funcinterval Time interval between the same function, tracepoint
# as a histogram.
#
# USAGE: funcinterval [-h] [-p PID] [-i INTERVAL] [-T] [-u] [-m] [-v] pattern
#
# Run "funcinterval -h" for full usage.
#
# Copyright (c) 2020 Realtek, Inc.
# Licensed under the Apache License, Version 2.0 (the "License")
#
# 03-Jun-2020 Edward Wu Referenced funclatency and created this.
from __future__ import print_function
from bcc import BPF
from time import sleep, strftime
import argparse
import signal
# arguments
examples = """examples:
# time the interval of do_sys_open()
./funcinterval do_sys_open
# time the interval of xhci_ring_ep_doorbell(), in microseconds
./funcinterval -u xhci_ring_ep_doorbell
# time the interval of do_nanosleep(), in milliseconds
./funcinterval -m do_nanosleep
# output every 5 seconds, with timestamps
./funcinterval -mTi 5 vfs_read
# time process 181 only
./funcinterval -p 181 vfs_read
# time the interval of mm_vmscan_direct_reclaim_begin tracepoint
./funcinterval t:vmscan:mm_vmscan_direct_reclaim_begin
"""
parser = argparse.ArgumentParser(
description="Time interval and print latency as a histogram",
formatter_class=argparse.RawDescriptionHelpFormatter,
epilog=examples)
parser.add_argument("-p", "--pid", type=int,
help="trace this PID only")
parser.add_argument("-i", "--interval", type=int,
help="summary interval, in seconds")
parser.add_argument("-d", "--duration", type=int,
help="total duration of trace, in seconds")
parser.add_argument("-T", "--timestamp", action="store_true",
help="include timestamp on output")
parser.add_argument("-u", "--microseconds", action="store_true",
help="microsecond histogram")
parser.add_argument("-m", "--milliseconds", action="store_true",
help="millisecond histogram")
parser.add_argument("-v", "--verbose", action="store_true",
help="print the BPF program (for debugging purposes)")
parser.add_argument("pattern",
help="Function/Tracepoint name for tracing")
parser.add_argument("--ebpf", action="store_true",
help=argparse.SUPPRESS)
args = parser.parse_args()
if args.duration and not args.interval:
args.interval = args.duration
if not args.interval:
args.interval = 99999999
def bail(error):
print("Error: " + error)
exit(1)
parts = args.pattern.split(':')
if len(parts) == 1:
attach_type = "function"
pattern = args.pattern
elif len(parts) == 3:
attach_type = "tracepoint"
pattern = ':'.join(parts[1:])
else:
bail("unrecognized pattern format '%s'" % pattern)
# define BPF program
bpf_text = """
#include <uapi/linux/ptrace.h>
BPF_HASH(start, u32, u64, 1);
BPF_HISTOGRAM(dist);
int trace_func_entry(struct pt_regs *ctx)
{
u64 pid_tgid = bpf_get_current_pid_tgid();
u32 index = 0, tgid = pid_tgid >> 32;
u64 *tsp, ts = bpf_ktime_get_ns(), delta;
FILTER
tsp = start.lookup(&index);
if (tsp == 0)
goto out;
delta = ts - *tsp;
FACTOR
// store as histogram
dist.increment(bpf_log2l(delta));
out:
start.update(&index, &ts);
return 0;
}
"""
# code substitutions
if args.pid:
bpf_text = bpf_text.replace('FILTER',
'if (tgid != %d) { return 0; }' % args.pid)
else:
bpf_text = bpf_text.replace('FILTER', '')
if args.milliseconds:
bpf_text = bpf_text.replace('FACTOR', 'delta /= 1000000;')
label = "msecs"
elif args.microseconds:
bpf_text = bpf_text.replace('FACTOR', 'delta /= 1000;')
label = "usecs"
else:
bpf_text = bpf_text.replace('FACTOR', '')
label = "nsecs"
if args.verbose or args.ebpf:
print(bpf_text)
if args.ebpf:
exit()
# signal handler
def signal_ignore(signal, frame):
print()
# load BPF program
b = BPF(text=bpf_text)
if len(parts) == 1:
b.attach_kprobe(event=pattern, fn_name="trace_func_entry")
matched = b.num_open_kprobes()
elif len(parts) == 3:
b.attach_tracepoint(tp=pattern, fn_name="trace_func_entry")
matched = b.num_open_tracepoints()
if matched == 0:
print("0 %s matched by \"%s\". Exiting." % (attach_type, pattern))
exit()
# header
print("Tracing %s for \"%s\"... Hit Ctrl-C to end." %
(attach_type, pattern))
exiting = 0 if args.interval else 1
seconds = 0
dist = b.get_table("dist")
start = b.get_table("start")
while (1):
try:
sleep(args.interval)
seconds += args.interval
except KeyboardInterrupt:
exiting = 1
# as cleanup can take many seconds, trap Ctrl-C:
signal.signal(signal.SIGINT, signal_ignore)
if args.duration and seconds >= args.duration:
exiting = 1
print()
if args.timestamp:
print("%-8s\n" % strftime("%H:%M:%S"), end="")
dist.print_log2_hist(label)
dist.clear()
start.clear()
if exiting:
print("Detaching...")
exit()
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