You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
146 lines
4.1 KiB
146 lines
4.1 KiB
#!/usr/bin/env python
|
|
# @lint-avoid-python-3-compatibility-imports
|
|
#
|
|
# biolatency Summarize block device I/O latency as a histogram.
|
|
# For Linux, uses BCC, eBPF.
|
|
#
|
|
# USAGE: biolatency [-h] [-T] [-Q] [-m] [-D] [interval] [count]
|
|
#
|
|
# Copyright (c) 2015 Brendan Gregg.
|
|
# Licensed under the Apache License, Version 2.0 (the "License")
|
|
#
|
|
# 20-Sep-2015 Brendan Gregg Created this.
|
|
|
|
from __future__ import print_function
|
|
from bcc import BPF
|
|
from time import sleep, strftime
|
|
import argparse
|
|
|
|
# arguments
|
|
examples = """examples:
|
|
./biolatency # summarize block I/O latency as a histogram
|
|
./biolatency 1 10 # print 1 second summaries, 10 times
|
|
./biolatency -mT 1 # 1s summaries, milliseconds, and timestamps
|
|
./biolatency -Q # include OS queued time in I/O time
|
|
./biolatency -D # show each disk device separately
|
|
"""
|
|
parser = argparse.ArgumentParser(
|
|
description="Summarize block device I/O latency as a histogram",
|
|
formatter_class=argparse.RawDescriptionHelpFormatter,
|
|
epilog=examples)
|
|
parser.add_argument("-T", "--timestamp", action="store_true",
|
|
help="include timestamp on output")
|
|
parser.add_argument("-Q", "--queued", action="store_true",
|
|
help="include OS queued time in I/O time")
|
|
parser.add_argument("-m", "--milliseconds", action="store_true",
|
|
help="millisecond histogram")
|
|
parser.add_argument("-D", "--disks", action="store_true",
|
|
help="print a histogram per disk device")
|
|
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
|
|
|
|
# define BPF program
|
|
bpf_text = """
|
|
#include <uapi/linux/ptrace.h>
|
|
#include <linux/blkdev.h>
|
|
|
|
typedef struct disk_key {
|
|
char disk[DISK_NAME_LEN];
|
|
u64 slot;
|
|
} disk_key_t;
|
|
BPF_HASH(start, struct request *);
|
|
STORAGE
|
|
|
|
// time block I/O
|
|
int trace_req_start(struct pt_regs *ctx, struct request *req)
|
|
{
|
|
u64 ts = bpf_ktime_get_ns();
|
|
start.update(&req, &ts);
|
|
return 0;
|
|
}
|
|
|
|
// output
|
|
int trace_req_done(struct pt_regs *ctx, struct request *req)
|
|
{
|
|
u64 *tsp, delta;
|
|
|
|
// fetch timestamp and calculate delta
|
|
tsp = start.lookup(&req);
|
|
if (tsp == 0) {
|
|
return 0; // missed issue
|
|
}
|
|
delta = bpf_ktime_get_ns() - *tsp;
|
|
FACTOR
|
|
|
|
// store as histogram
|
|
STORE
|
|
|
|
start.delete(&req);
|
|
return 0;
|
|
}
|
|
"""
|
|
|
|
# code substitutions
|
|
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.disks:
|
|
bpf_text = bpf_text.replace('STORAGE',
|
|
'BPF_HISTOGRAM(dist, disk_key_t);')
|
|
bpf_text = bpf_text.replace('STORE',
|
|
'disk_key_t key = {.slot = bpf_log2l(delta)}; ' +
|
|
'void *__tmp = (void *)req->rq_disk->disk_name; ' +
|
|
'bpf_probe_read(&key.disk, sizeof(key.disk), __tmp); ' +
|
|
'dist.increment(key);')
|
|
else:
|
|
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()
|
|
|
|
# load BPF program
|
|
b = BPF(text=bpf_text)
|
|
if args.queued:
|
|
b.attach_kprobe(event="blk_account_io_start", fn_name="trace_req_start")
|
|
else:
|
|
if BPF.get_kprobe_functions(b'blk_start_request'):
|
|
b.attach_kprobe(event="blk_start_request", fn_name="trace_req_start")
|
|
b.attach_kprobe(event="blk_mq_start_request", fn_name="trace_req_start")
|
|
b.attach_kprobe(event="blk_account_io_done",
|
|
fn_name="trace_req_done")
|
|
|
|
print("Tracing block device I/O... 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="")
|
|
|
|
dist.print_log2_hist(label, "disk")
|
|
dist.clear()
|
|
|
|
countdown -= 1
|
|
if exiting or countdown == 0:
|
|
exit()
|