blob: 0b2e50c7b72bfe43913d15a37a4777da2903a3bd [file] [log] [blame]
#!/usr/bin/python
# @lint-avoid-python-3-compatibility-imports
#
# softirqs Summarize soft IRQ (interrupt) event time.
# For Linux, uses BCC, eBPF.
#
# USAGE: softirqs [-h] [-T] [-N] [-d] [interval] [count]
#
# Copyright (c) 2015 Brendan Gregg.
# Licensed under the Apache License, Version 2.0 (the "License")
#
# 20-Oct-2015 Brendan Gregg Created this.
from __future__ import print_function
from bcc import BPF
from time import sleep, strftime
import argparse
# arguments
examples = """examples:
./softirqs # sum soft irq event time
./softirqs -d # show soft irq event time as histograms
./softirqs 1 10 # print 1 second summaries, 10 times
./softirqs -NT 1 # 1s summaries, nanoseconds, and timestamps
"""
parser = argparse.ArgumentParser(
description="Summarize soft irq event time as histograms",
formatter_class=argparse.RawDescriptionHelpFormatter,
epilog=examples)
parser.add_argument("-T", "--timestamp", action="store_true",
help="include timestamp on output")
parser.add_argument("-N", "--nanoseconds", action="store_true",
help="output in nanoseconds")
parser.add_argument("-d", "--dist", action="store_true",
help="show distributions as histograms")
parser.add_argument("interval", nargs="?", default=99999999,
help="output interval, in seconds")
parser.add_argument("count", nargs="?", default=99999999,
help="number of outputs")
args = parser.parse_args()
countdown = int(args.count)
if args.nanoseconds:
factor = 1
label = "nsecs"
else:
factor = 1000
label = "usecs"
debug = 0
# define BPF program
bpf_text = """
#include <uapi/linux/ptrace.h>
typedef struct irq_key {
u64 ip;
u64 slot;
} irq_key_t;
BPF_HASH(start, u32);
BPF_HASH(iptr, u32);
BPF_HISTOGRAM(dist, irq_key_t);
// time IRQ
int trace_start(struct pt_regs *ctx)
{
u32 pid = bpf_get_current_pid_tgid();
u64 ip = PT_REGS_IP(ctx), ts = bpf_ktime_get_ns();
start.update(&pid, &ts);
iptr.update(&pid, &ip);
return 0;
}
int trace_completion(struct pt_regs *ctx)
{
u64 *tsp, delta, ip, *ipp;
u32 pid = bpf_get_current_pid_tgid();
// fetch timestamp and calculate delta
tsp = start.lookup(&pid);
ipp = iptr.lookup(&pid);
if (tsp == 0 || ipp == 0) {
return 0; // missed start
}
delta = bpf_ktime_get_ns() - *tsp;
ip = *ipp;
// store as sum or histogram
STORE
start.delete(&pid);
iptr.delete(&pid);
return 0;
}
"""
# code substitutions
if args.dist:
bpf_text = bpf_text.replace('STORE',
'irq_key_t key = {.ip = ip, .slot = bpf_log2l(delta)};' +
'dist.increment(key);')
else:
bpf_text = bpf_text.replace('STORE',
'irq_key_t key = {.ip = ip, .slot = 0 /* ignore */};' +
'u64 zero = 0, *vp = dist.lookup_or_init(&key, &zero);' +
'(*vp) += delta;')
if debug:
print(bpf_text)
# load BPF program
b = BPF(text=bpf_text)
# this should really use irq:softirq_entry/exit tracepoints; for now the
# soft irq functions are individually traced (search your kernel for
# open_softirq() calls, and adjust the following list as needed).
for softirqfunc in ("blk_iopoll_softirq", "blk_done_softirq",
"rcu_process_callbacks", "run_rebalance_domains", "tasklet_action",
"tasklet_hi_action", "run_timer_softirq", "net_tx_action",
"net_rx_action"):
b.attach_kprobe(event=softirqfunc, fn_name="trace_start")
b.attach_kretprobe(event=softirqfunc, fn_name="trace_completion")
print("Tracing soft irq event time... Hit Ctrl-C to end.")
# output
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="")
if args.dist:
dist.print_log2_hist(label, "softirq", section_print_fn=b.ksym)
else:
print("%-26s %11s" % ("SOFTIRQ", "TOTAL_" + label))
for k, v in sorted(dist.items(), key=lambda dist: dist[1].value):
print("%-26s %11d" % (b.ksym(k.ip), v.value / factor))
dist.clear()
countdown -= 1
if exiting or countdown == 0:
exit()