forked from iovisor/bcc
-
Notifications
You must be signed in to change notification settings - Fork 0
/
biolatency.bpf.c
115 lines (97 loc) · 2.58 KB
/
biolatency.bpf.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2020 Wenbo Zhang
#include "vmlinux.h"
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_core_read.h>
#include <bpf/bpf_tracing.h>
#include "biolatency.h"
#include "bits.bpf.h"
#define MAX_ENTRIES 10240
const volatile bool targ_per_disk = false;
const volatile bool targ_per_flag = false;
const volatile bool targ_queued = false;
const volatile bool targ_ms = false;
const volatile dev_t targ_dev = -1;
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__uint(max_entries, MAX_ENTRIES);
__type(key, struct request *);
__type(value, u64);
__uint(map_flags, BPF_F_NO_PREALLOC);
} start SEC(".maps");
static struct hist initial_hist;
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__uint(max_entries, MAX_ENTRIES);
__type(key, struct hist_key);
__type(value, struct hist);
__uint(map_flags, BPF_F_NO_PREALLOC);
} hists SEC(".maps");
static __always_inline
int trace_rq_start(struct request *rq)
{
u64 ts = bpf_ktime_get_ns();
if (targ_dev != -1) {
struct gendisk *disk = BPF_CORE_READ(rq, rq_disk);
dev_t dev;
dev = disk ? MKDEV(BPF_CORE_READ(disk, major),
BPF_CORE_READ(disk, first_minor)) : 0;
if (targ_dev != dev)
return 0;
}
bpf_map_update_elem(&start, &rq, &ts, 0);
return 0;
}
SEC("tp_btf/block_rq_insert")
int BPF_PROG(block_rq_insert, struct request_queue *q, struct request *rq)
{
return trace_rq_start(rq);
}
SEC("tp_btf/block_rq_issue")
int BPF_PROG(block_rq_issue, struct request_queue *q, struct request *rq)
{
if (targ_queued && BPF_CORE_READ(q, elevator))
return 0;
return trace_rq_start(rq);
}
SEC("tp_btf/block_rq_complete")
int BPF_PROG(block_rq_complete, struct request *rq, int error,
unsigned int nr_bytes)
{
u64 slot, *tsp, ts = bpf_ktime_get_ns();
struct hist_key hkey = {};
struct hist *histp;
s64 delta;
tsp = bpf_map_lookup_elem(&start, &rq);
if (!tsp)
return 0;
delta = (s64)(ts - *tsp);
if (delta < 0)
goto cleanup;
if (targ_per_disk) {
struct gendisk *disk = BPF_CORE_READ(rq, rq_disk);
hkey.dev = disk ? MKDEV(BPF_CORE_READ(disk, major),
BPF_CORE_READ(disk, first_minor)) : 0;
}
if (targ_per_flag)
hkey.cmd_flags = rq->cmd_flags;
histp = bpf_map_lookup_elem(&hists, &hkey);
if (!histp) {
bpf_map_update_elem(&hists, &hkey, &initial_hist, 0);
histp = bpf_map_lookup_elem(&hists, &hkey);
if (!histp)
goto cleanup;
}
if (targ_ms)
delta /= 1000000U;
else
delta /= 1000U;
slot = log2l(delta);
if (slot >= MAX_SLOTS)
slot = MAX_SLOTS - 1;
__sync_fetch_and_add(&histp->slots[slot], 1);
cleanup:
bpf_map_delete_elem(&start, &rq);
return 0;
}
char LICENSE[] SEC("license") = "GPL";