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hardirqs.py
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hardirqs.py
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#!/usr/bin/env python
# @lint-avoid-python-3-compatibility-imports
#
# hardirqs Summarize hard IRQ (interrupt) event time.
# For Linux, uses BCC, eBPF.
#
# USAGE: hardirqs [-h] [-T] [-N] [-C] [-d] [-c CPU] [interval] [outputs]
#
# Thanks Amer Ather for help understanding irq behavior.
#
# Copyright (c) 2015 Brendan Gregg.
# Licensed under the Apache License, Version 2.0 (the "License")
#
# 19-Oct-2015 Brendan Gregg Created this.
# 22-May-2021 Hengqi Chen Migrated to kernel tracepoints.
# 07-Mar-2022 Rocky Xing Added CPU filter support.
from __future__ import print_function
from bcc import BPF
from time import sleep, strftime
import argparse
import sys
# arguments
examples = """examples:
./hardirqs # sum hard irq event time
./hardirqs -d # show hard irq event time as histograms
./hardirqs 1 10 # print 1 second summaries, 10 times
./hardirqs -NT 1 # 1s summaries, nanoseconds, and timestamps
./hardirqs -c 1 # sum hard irq event time on CPU 1 only
"""
parser = argparse.ArgumentParser(
description="Summarize hard 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("-C", "--count", action="store_true",
help="show event counts instead of timing")
parser.add_argument("-d", "--dist", action="store_true",
help="show distributions as histograms")
parser.add_argument("-c", "--cpu", type=int,
help="trace this CPU only")
parser.add_argument("interval", nargs="?", default=99999999,
help="output interval, in seconds")
parser.add_argument("outputs", nargs="?", default=99999999,
help="number of outputs")
parser.add_argument("--ebpf", action="store_true",
help=argparse.SUPPRESS)
args = parser.parse_args()
countdown = int(args.outputs)
if args.count and (args.dist or args.nanoseconds):
print("The --count option can't be used with time-based options")
exit()
if args.count:
factor = 1
label = "count"
elif args.nanoseconds:
factor = 1
label = "nsecs"
else:
factor = 1000
label = "usecs"
debug = 0
# define BPF program
bpf_text = """
#include <uapi/linux/ptrace.h>
#include <linux/irq.h>
#include <linux/irqdesc.h>
#include <linux/interrupt.h>
// Add cpu_id as part of key for irq entry event to handle the case which irq
// is triggered while idle thread(swapper/x, tid=0) for each cpu core.
// Please see more detail at pull request #2804, #3733.
typedef struct entry_key {
u32 tid;
u32 cpu_id;
} entry_key_t;
typedef struct irq_key {
char name[32];
u64 slot;
} irq_key_t;
typedef struct irq_name {
char name[32];
} irq_name_t;
BPF_HASH(start, entry_key_t);
BPF_HASH(irqnames, entry_key_t, irq_name_t);
BPF_HISTOGRAM(dist, irq_key_t);
"""
bpf_text_count = """
TRACEPOINT_PROBE(irq, irq_handler_entry)
{
struct entry_key key = {};
irq_name_t name = {};
u32 cpu = bpf_get_smp_processor_id();
FILTER_CPU
key.tid = bpf_get_current_pid_tgid();
key.cpu_id = cpu;
TP_DATA_LOC_READ_STR(&name.name, name, sizeof(name));
irqnames.update(&key, &name);
return 0;
}
TRACEPOINT_PROBE(irq, irq_handler_exit)
{
struct entry_key key = {};
u32 cpu = bpf_get_smp_processor_id();
FILTER_CPU
key.tid = bpf_get_current_pid_tgid();
key.cpu_id = cpu;
// check ret value of irq handler is not IRQ_NONE to make sure
// the current event belong to this irq handler
if (args->ret != IRQ_NONE) {
irq_name_t *namep;
namep = irqnames.lookup(&key);
if (namep == 0) {
return 0; // missed irq name
}
char *name = (char *)namep->name;
irq_key_t key = {.slot = 0 /* ignore */};
bpf_probe_read_kernel(&key.name, sizeof(key.name), name);
dist.atomic_increment(key);
}
irqnames.delete(&key);
return 0;
}
"""
bpf_text_time = """
TRACEPOINT_PROBE(irq, irq_handler_entry)
{
u64 ts = bpf_ktime_get_ns();
irq_name_t name = {};
struct entry_key key = {};
u32 cpu = bpf_get_smp_processor_id();
FILTER_CPU
key.tid = bpf_get_current_pid_tgid();
key.cpu_id = cpu;
TP_DATA_LOC_READ_STR(&name.name, name, sizeof(name));
irqnames.update(&key, &name);
start.update(&key, &ts);
return 0;
}
TRACEPOINT_PROBE(irq, irq_handler_exit)
{
u64 *tsp, delta;
irq_name_t *namep;
struct entry_key key = {};
u32 cpu = bpf_get_smp_processor_id();
key.tid = bpf_get_current_pid_tgid();
key.cpu_id = cpu;
// check ret value of irq handler is not IRQ_NONE to make sure
// the current event belong to this irq handler
if (args->ret != IRQ_NONE) {
// fetch timestamp and calculate delta
tsp = start.lookup(&key);
namep = irqnames.lookup(&key);
if (tsp == 0 || namep == 0) {
return 0; // missed start
}
char *name = (char *)namep->name;
delta = bpf_ktime_get_ns() - *tsp;
// store as sum or histogram
STORE
}
start.delete(&key);
irqnames.delete(&key);
return 0;
}
"""
if args.count:
bpf_text += bpf_text_count
else:
bpf_text += bpf_text_time
# code substitutions
if args.dist:
bpf_text = bpf_text.replace('STORE',
'irq_key_t key = {.slot = bpf_log2l(delta / %d)};' % factor +
'bpf_probe_read_kernel(&key.name, sizeof(key.name), name);' +
'dist.atomic_increment(key);')
else:
bpf_text = bpf_text.replace('STORE',
'irq_key_t key = {.slot = 0 /* ignore */};' +
'bpf_probe_read_kernel(&key.name, sizeof(key.name), name);' +
'dist.atomic_increment(key, delta);')
if args.cpu is not None:
bpf_text = bpf_text.replace('FILTER_CPU',
'if (cpu != %d) { return 0; }' % int(args.cpu))
else:
bpf_text = bpf_text.replace('FILTER_CPU', '')
if debug or args.ebpf:
print(bpf_text)
if args.ebpf:
exit()
# load BPF program
b = BPF(text=bpf_text)
if args.count:
print("Tracing hard irq events... Hit Ctrl-C to end.")
else:
print("Tracing hard 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, "hardirq", section_print_fn=bytes.decode)
else:
print("%-26s %11s" % ("HARDIRQ", "TOTAL_" + label))
for k, v in sorted(dist.items(), key=lambda dist: dist[1].value):
print("%-26s %11d" % (k.name.decode('utf-8', 'replace'), v.value / factor))
dist.clear()
sys.stdout.flush()
countdown -= 1
if exiting or countdown == 0:
exit()