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-rw-r--r--samples/bpf/Makefile4
-rw-r--r--samples/bpf/tracex3_kern.c89
-rw-r--r--samples/bpf/tracex3_user.c150
3 files changed, 243 insertions, 0 deletions
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 6dd272143733..dcd850546d52 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -8,6 +8,7 @@ hostprogs-y += sockex1
8hostprogs-y += sockex2 8hostprogs-y += sockex2
9hostprogs-y += tracex1 9hostprogs-y += tracex1
10hostprogs-y += tracex2 10hostprogs-y += tracex2
11hostprogs-y += tracex3
11 12
12test_verifier-objs := test_verifier.o libbpf.o 13test_verifier-objs := test_verifier.o libbpf.o
13test_maps-objs := test_maps.o libbpf.o 14test_maps-objs := test_maps.o libbpf.o
@@ -16,6 +17,7 @@ sockex1-objs := bpf_load.o libbpf.o sockex1_user.o
16sockex2-objs := bpf_load.o libbpf.o sockex2_user.o 17sockex2-objs := bpf_load.o libbpf.o sockex2_user.o
17tracex1-objs := bpf_load.o libbpf.o tracex1_user.o 18tracex1-objs := bpf_load.o libbpf.o tracex1_user.o
18tracex2-objs := bpf_load.o libbpf.o tracex2_user.o 19tracex2-objs := bpf_load.o libbpf.o tracex2_user.o
20tracex3-objs := bpf_load.o libbpf.o tracex3_user.o
19 21
20# Tell kbuild to always build the programs 22# Tell kbuild to always build the programs
21always := $(hostprogs-y) 23always := $(hostprogs-y)
@@ -23,6 +25,7 @@ always += sockex1_kern.o
23always += sockex2_kern.o 25always += sockex2_kern.o
24always += tracex1_kern.o 26always += tracex1_kern.o
25always += tracex2_kern.o 27always += tracex2_kern.o
28always += tracex3_kern.o
26 29
27HOSTCFLAGS += -I$(objtree)/usr/include 30HOSTCFLAGS += -I$(objtree)/usr/include
28 31
@@ -31,6 +34,7 @@ HOSTLOADLIBES_sockex1 += -lelf
31HOSTLOADLIBES_sockex2 += -lelf 34HOSTLOADLIBES_sockex2 += -lelf
32HOSTLOADLIBES_tracex1 += -lelf 35HOSTLOADLIBES_tracex1 += -lelf
33HOSTLOADLIBES_tracex2 += -lelf 36HOSTLOADLIBES_tracex2 += -lelf
37HOSTLOADLIBES_tracex3 += -lelf
34 38
35# point this to your LLVM backend with bpf support 39# point this to your LLVM backend with bpf support
36LLC=$(srctree)/tools/bpf/llvm/bld/Debug+Asserts/bin/llc 40LLC=$(srctree)/tools/bpf/llvm/bld/Debug+Asserts/bin/llc
diff --git a/samples/bpf/tracex3_kern.c b/samples/bpf/tracex3_kern.c
new file mode 100644
index 000000000000..255ff2792366
--- /dev/null
+++ b/samples/bpf/tracex3_kern.c
@@ -0,0 +1,89 @@
1/* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com
2 *
3 * This program is free software; you can redistribute it and/or
4 * modify it under the terms of version 2 of the GNU General Public
5 * License as published by the Free Software Foundation.
6 */
7#include <linux/skbuff.h>
8#include <linux/netdevice.h>
9#include <linux/version.h>
10#include <uapi/linux/bpf.h>
11#include "bpf_helpers.h"
12
13struct bpf_map_def SEC("maps") my_map = {
14 .type = BPF_MAP_TYPE_HASH,
15 .key_size = sizeof(long),
16 .value_size = sizeof(u64),
17 .max_entries = 4096,
18};
19
20/* kprobe is NOT a stable ABI. If kernel internals change this bpf+kprobe
21 * example will no longer be meaningful
22 */
23SEC("kprobe/blk_mq_start_request")
24int bpf_prog1(struct pt_regs *ctx)
25{
26 long rq = ctx->di;
27 u64 val = bpf_ktime_get_ns();
28
29 bpf_map_update_elem(&my_map, &rq, &val, BPF_ANY);
30 return 0;
31}
32
33static unsigned int log2l(unsigned long long n)
34{
35#define S(k) if (n >= (1ull << k)) { i += k; n >>= k; }
36 int i = -(n == 0);
37 S(32); S(16); S(8); S(4); S(2); S(1);
38 return i;
39#undef S
40}
41
42#define SLOTS 100
43
44struct bpf_map_def SEC("maps") lat_map = {
45 .type = BPF_MAP_TYPE_ARRAY,
46 .key_size = sizeof(u32),
47 .value_size = sizeof(u64),
48 .max_entries = SLOTS,
49};
50
51SEC("kprobe/blk_update_request")
52int bpf_prog2(struct pt_regs *ctx)
53{
54 long rq = ctx->di;
55 u64 *value, l, base;
56 u32 index;
57
58 value = bpf_map_lookup_elem(&my_map, &rq);
59 if (!value)
60 return 0;
61
62 u64 cur_time = bpf_ktime_get_ns();
63 u64 delta = cur_time - *value;
64
65 bpf_map_delete_elem(&my_map, &rq);
66
67 /* the lines below are computing index = log10(delta)*10
68 * using integer arithmetic
69 * index = 29 ~ 1 usec
70 * index = 59 ~ 1 msec
71 * index = 89 ~ 1 sec
72 * index = 99 ~ 10sec or more
73 * log10(x)*10 = log2(x)*10/log2(10) = log2(x)*3
74 */
75 l = log2l(delta);
76 base = 1ll << l;
77 index = (l * 64 + (delta - base) * 64 / base) * 3 / 64;
78
79 if (index >= SLOTS)
80 index = SLOTS - 1;
81
82 value = bpf_map_lookup_elem(&lat_map, &index);
83 if (value)
84 __sync_fetch_and_add((long *)value, 1);
85
86 return 0;
87}
88char _license[] SEC("license") = "GPL";
89u32 _version SEC("version") = LINUX_VERSION_CODE;
diff --git a/samples/bpf/tracex3_user.c b/samples/bpf/tracex3_user.c
new file mode 100644
index 000000000000..0aaa933ab938
--- /dev/null
+++ b/samples/bpf/tracex3_user.c
@@ -0,0 +1,150 @@
1/* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com
2 *
3 * This program is free software; you can redistribute it and/or
4 * modify it under the terms of version 2 of the GNU General Public
5 * License as published by the Free Software Foundation.
6 */
7#include <stdio.h>
8#include <stdlib.h>
9#include <signal.h>
10#include <unistd.h>
11#include <stdbool.h>
12#include <string.h>
13#include <linux/bpf.h>
14#include "libbpf.h"
15#include "bpf_load.h"
16
17#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))
18
19#define SLOTS 100
20
21static void clear_stats(int fd)
22{
23 __u32 key;
24 __u64 value = 0;
25
26 for (key = 0; key < SLOTS; key++)
27 bpf_update_elem(fd, &key, &value, BPF_ANY);
28}
29
30const char *color[] = {
31 "\033[48;5;255m",
32 "\033[48;5;252m",
33 "\033[48;5;250m",
34 "\033[48;5;248m",
35 "\033[48;5;246m",
36 "\033[48;5;244m",
37 "\033[48;5;242m",
38 "\033[48;5;240m",
39 "\033[48;5;238m",
40 "\033[48;5;236m",
41 "\033[48;5;234m",
42 "\033[48;5;232m",
43};
44const int num_colors = ARRAY_SIZE(color);
45
46const char nocolor[] = "\033[00m";
47
48const char *sym[] = {
49 " ",
50 " ",
51 ".",
52 ".",
53 "*",
54 "*",
55 "o",
56 "o",
57 "O",
58 "O",
59 "#",
60 "#",
61};
62
63bool full_range = false;
64bool text_only = false;
65
66static void print_banner(void)
67{
68 if (full_range)
69 printf("|1ns |10ns |100ns |1us |10us |100us"
70 " |1ms |10ms |100ms |1s |10s\n");
71 else
72 printf("|1us |10us |100us |1ms |10ms "
73 "|100ms |1s |10s\n");
74}
75
76static void print_hist(int fd)
77{
78 __u32 key;
79 __u64 value;
80 __u64 cnt[SLOTS];
81 __u64 max_cnt = 0;
82 __u64 total_events = 0;
83
84 for (key = 0; key < SLOTS; key++) {
85 value = 0;
86 bpf_lookup_elem(fd, &key, &value);
87 cnt[key] = value;
88 total_events += value;
89 if (value > max_cnt)
90 max_cnt = value;
91 }
92 clear_stats(fd);
93 for (key = full_range ? 0 : 29; key < SLOTS; key++) {
94 int c = num_colors * cnt[key] / (max_cnt + 1);
95
96 if (text_only)
97 printf("%s", sym[c]);
98 else
99 printf("%s %s", color[c], nocolor);
100 }
101 printf(" # %lld\n", total_events);
102}
103
104int main(int ac, char **argv)
105{
106 char filename[256];
107 int i;
108
109 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
110
111 if (load_bpf_file(filename)) {
112 printf("%s", bpf_log_buf);
113 return 1;
114 }
115
116 for (i = 1; i < ac; i++) {
117 if (strcmp(argv[i], "-a") == 0) {
118 full_range = true;
119 } else if (strcmp(argv[i], "-t") == 0) {
120 text_only = true;
121 } else if (strcmp(argv[i], "-h") == 0) {
122 printf("Usage:\n"
123 " -a display wider latency range\n"
124 " -t text only\n");
125 return 1;
126 }
127 }
128
129 printf(" heatmap of IO latency\n");
130 if (text_only)
131 printf(" %s", sym[num_colors - 1]);
132 else
133 printf(" %s %s", color[num_colors - 1], nocolor);
134 printf(" - many events with this latency\n");
135
136 if (text_only)
137 printf(" %s", sym[0]);
138 else
139 printf(" %s %s", color[0], nocolor);
140 printf(" - few events\n");
141
142 for (i = 0; ; i++) {
143 if (i % 20 == 0)
144 print_banner();
145 print_hist(map_fd[1]);
146 sleep(2);
147 }
148
149 return 0;
150}
generated by cgit v1.2.2 (git 2.25.0) at 2026-05-27 12:01:51 -0400