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#!/usr/bin/python
# @lint-avoid-python-3-compatibility-imports
#
# cpudist Summarize on- and off-CPU time per task as a histogram.
#
# USAGE: cpudist [-h] [-O] [-T] [-m] [-P] [-L] [-p PID] [interval] [count]
#
# This measures the time a task spends on or off the CPU, and shows this time
# as a histogram, optionally per-process.
#
# Copyright 2016 Sasha Goldshtein
# Licensed under the Apache License, Version 2.0 (the "License")
from __future__ import print_function
from bcc import BPF
from time import sleep, strftime
import argparse
examples = """examples:
cpudist # summarize on-CPU time as a histogram
cpudist -O # summarize off-CPU time as a histogram
cpudist 1 10 # print 1 second summaries, 10 times
cpudist -mT 1 # 1s summaries, milliseconds, and timestamps
cpudist -P # show each PID separately
cpudist -p 185 # trace PID 185 only
"""
parser = argparse.ArgumentParser(
description="Summarize on-CPU time per task as a histogram.",
formatter_class=argparse.RawDescriptionHelpFormatter,
epilog=examples)
parser.add_argument("-O", "--offcpu", action="store_true",
help="measure off-CPU time")
parser.add_argument("-T", "--timestamp", action="store_true",
help="include timestamp on output")
parser.add_argument("-m", "--milliseconds", action="store_true",
help="millisecond histogram")
parser.add_argument("-P", "--pids", action="store_true",
help="print a histogram per process ID")
parser.add_argument("-L", "--tids", action="store_true",
help="print a histogram per thread ID")
parser.add_argument("-p", "--pid",
help="trace this PID only")
parser.add_argument("interval", nargs="?", default=99999999,
help="output interval, in seconds")
parser.add_argument("count", nargs="?", default=99999999,
help="number of outputs")
parser.add_argument("--ebpf", action="store_true",
help=argparse.SUPPRESS)
args = parser.parse_args()
countdown = int(args.count)
debug = 0
bpf_text = """#include <uapi/linux/ptrace.h>
#include <linux/sched.h>
"""
if not args.offcpu:
bpf_text += "#define ONCPU\n"
bpf_text += """
typedef struct pid_key {
u64 id;
u64 slot;
} pid_key_t;
BPF_HASH(start, u32, u64);
STORAGE
static inline void store_start(u32 tgid, u32 pid, u64 ts)
{
if (FILTER)
return;
start.update(&pid, &ts);
}
static inline void update_hist(u32 tgid, u32 pid, u64 ts)
{
if (FILTER)
return;
u64 *tsp = start.lookup(&pid);
if (tsp == 0)
return;
if (ts < *tsp) {
// Probably a clock issue where the recorded on-CPU event had a
// timestamp later than the recorded off-CPU event, or vice versa.
return;
}
u64 delta = ts - *tsp;
FACTOR
STORE
}
int sched_switch(struct pt_regs *ctx, struct task_struct *prev)
{
u64 ts = bpf_ktime_get_ns();
u64 pid_tgid = bpf_get_current_pid_tgid();
u32 tgid = pid_tgid >> 32, pid = pid_tgid;
#ifdef ONCPU
if (prev->state == TASK_RUNNING) {
#else
if (1) {
#endif
u32 prev_pid = prev->pid;
u32 prev_tgid = prev->tgid;
#ifdef ONCPU
update_hist(prev_tgid, prev_pid, ts);
#else
store_start(prev_tgid, prev_pid, ts);
#endif
}
BAIL:
#ifdef ONCPU
store_start(tgid, pid, ts);
#else
update_hist(tgid, pid, ts);
#endif
return 0;
}
"""
if args.pid:
bpf_text = bpf_text.replace('FILTER', 'tgid != %s' % args.pid)
else:
bpf_text = bpf_text.replace('FILTER', '0')
if args.milliseconds:
bpf_text = bpf_text.replace('FACTOR', 'delta /= 1000000;')
label = "msecs"
else:
bpf_text = bpf_text.replace('FACTOR', 'delta /= 1000;')
label = "usecs"
if args.pids or args.tids:
section = "pid"
pid = "tgid"
if args.tids:
pid = "pid"
section = "tid"
bpf_text = bpf_text.replace('STORAGE',
'BPF_HISTOGRAM(dist, pid_key_t);')
bpf_text = bpf_text.replace('STORE',
'pid_key_t key = {.id = ' + pid + ', .slot = bpf_log2l(delta)}; ' +
'dist.increment(key);')
else:
section = ""
bpf_text = bpf_text.replace('STORAGE', 'BPF_HISTOGRAM(dist);')
bpf_text = bpf_text.replace('STORE',
'dist.increment(bpf_log2l(delta));')
if debug or args.ebpf:
print(bpf_text)
if args.ebpf:
exit()
b = BPF(text=bpf_text)
b.attach_kprobe(event="finish_task_switch", fn_name="sched_switch")
print("Tracing %s-CPU time... Hit Ctrl-C to end." %
("off" if args.offcpu else "on"))
exiting = 0 if args.interval else 1
dist = b.get_table("dist")
while (1):
try:
sleep(int(args.interval))
except KeyboardInterrupt:
exiting = 1
print()
if args.timestamp:
print("%-8s\n" % strftime("%H:%M:%S"), end="")
def pid_to_comm(pid):
try:
comm = open("/proc/%d/comm" % pid, "r").read()
return "%d %s" % (pid, comm)
except IOError:
return str(pid)
dist.print_log2_hist(label, section, section_print_fn=pid_to_comm)
dist.clear()
countdown -= 1
if exiting or countdown == 0:
exit()