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Copy pathhardirqs
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·155 lines (138 loc) · 4.24 KB
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#!/usr/bin/python
#
# hardirqs Summarize hard IRQ (interrupt) event time.
# For Linux, uses BCC, eBPF.
#
# USAGE: hardirqs [-h] [-T] [-Q] [-m] [-D] [interval] [count]
#
# 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.
from __future__ import print_function
from bcc import BPF
from time import sleep, strftime
import argparse
### 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
"""
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("-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>
#include <linux/irq.h>
#include <linux/irqdesc.h>
#include <linux/interrupt.h>
typedef struct irq_key {
char name[32];
u64 slot;
} irq_key_t;
BPF_HASH(start, u32);
BPF_HASH(irqdesc, u32, struct irq_desc *);
BPF_HISTOGRAM(dist, irq_key_t);
// time IRQ
int trace_start(struct pt_regs *ctx, struct irq_desc *desc)
{
u32 pid = bpf_get_current_pid_tgid();
u64 ts = bpf_ktime_get_ns();
start.update(&pid, &ts);
irqdesc.update(&pid, &desc);
return 0;
}
int trace_completion(struct pt_regs *ctx)
{
u64 *tsp, delta;
struct irq_desc **descp;
u32 pid = bpf_get_current_pid_tgid();
// fetch timestamp and calculate delta
tsp = start.lookup(&pid);
descp = irqdesc.lookup(&pid);
if (tsp == 0 || descp == 0) {
return 0; // missed start
}
// Note: descp is a value from map, so '&' can be done without
// probe_read, but the next level irqaction * needs a probe read.
// Do these steps first after reading the map, otherwise some of these
// pointers may get pushed onto the stack and verifier will fail.
struct irqaction *action = 0;
bpf_probe_read(&action, sizeof(action), &(*descp)->action);
const char **namep = &action->name;
char *name = 0;
bpf_probe_read(&name, sizeof(name), namep);
delta = bpf_ktime_get_ns() - *tsp;
// store as sum or histogram
STORE
start.delete(&pid);
irqdesc.delete(&pid);
return 0;
}
"""
### code substitutions
if args.dist:
bpf_text = bpf_text.replace('STORE',
'irq_key_t key = {.slot = bpf_log2l(delta)};' +
'bpf_probe_read(&key.name, sizeof(key.name), name);' +
'dist.increment(key);')
else:
bpf_text = bpf_text.replace('STORE',
'irq_key_t key = {.slot = 0 /* ignore */};' +
'bpf_probe_read(&key.name, sizeof(key.name), name);' +
'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)
# these should really use irq:irq_handler_entry/exit tracepoints:
b.attach_kprobe(event="handle_irq_event_percpu", fn_name="trace_start")
b.attach_kretprobe(event="handle_irq_event_percpu", fn_name="trace_completion")
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")
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, v.value / factor))
dist.clear()
countdown -= 1
if exiting or countdown == 0:
exit()