Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
1// SPDX-License-Identifier: GPL-2.0
2#ifdef HAVE_BPF_SKEL
3#define _GNU_SOURCE
4#include "timerlat.h"
5#include "timerlat_bpf.h"
6#include "timerlat.skel.h"
7
8static struct timerlat_bpf *bpf;
9
10/*
11 * timerlat_bpf_init - load and initialize BPF program to collect timerlat data
12 */
13int timerlat_bpf_init(struct timerlat_params *params)
14{
15 int err;
16
17 debug_msg("Loading BPF program\n");
18
19 bpf = timerlat_bpf__open();
20 if (!bpf)
21 return 1;
22
23 /* Pass common options */
24 bpf->rodata->output_divisor = params->common.output_divisor;
25 bpf->rodata->entries = params->common.hist.entries;
26 bpf->rodata->irq_threshold = params->common.stop_us;
27 bpf->rodata->thread_threshold = params->common.stop_total_us;
28 bpf->rodata->aa_only = params->common.aa_only;
29
30 if (params->common.hist.entries != 0) {
31 /* Pass histogram options */
32 bpf->rodata->bucket_size = params->common.hist.bucket_size;
33
34 /* Set histogram array sizes */
35 bpf_map__set_max_entries(bpf->maps.hist_irq, params->common.hist.entries);
36 bpf_map__set_max_entries(bpf->maps.hist_thread, params->common.hist.entries);
37 bpf_map__set_max_entries(bpf->maps.hist_user, params->common.hist.entries);
38 } else {
39 /* No entries, disable histogram */
40 bpf_map__set_autocreate(bpf->maps.hist_irq, false);
41 bpf_map__set_autocreate(bpf->maps.hist_thread, false);
42 bpf_map__set_autocreate(bpf->maps.hist_user, false);
43 }
44
45 if (params->common.aa_only) {
46 /* Auto-analysis only, disable summary */
47 bpf_map__set_autocreate(bpf->maps.summary_irq, false);
48 bpf_map__set_autocreate(bpf->maps.summary_thread, false);
49 bpf_map__set_autocreate(bpf->maps.summary_user, false);
50 }
51
52 /* Load and verify BPF program */
53 err = timerlat_bpf__load(bpf);
54 if (err) {
55 timerlat_bpf__destroy(bpf);
56 return err;
57 }
58
59 return 0;
60}
61
62/*
63 * timerlat_bpf_attach - attach BPF program to collect timerlat data
64 */
65int timerlat_bpf_attach(void)
66{
67 debug_msg("Attaching BPF program\n");
68
69 return timerlat_bpf__attach(bpf);
70}
71
72/*
73 * timerlat_bpf_detach - detach BPF program to collect timerlat data
74 */
75void timerlat_bpf_detach(void)
76{
77 timerlat_bpf__detach(bpf);
78}
79
80/*
81 * timerlat_bpf_detach - destroy BPF program to collect timerlat data
82 */
83void timerlat_bpf_destroy(void)
84{
85 timerlat_bpf__destroy(bpf);
86}
87
88static int handle_rb_event(void *ctx, void *data, size_t data_sz)
89{
90 return 0;
91}
92
93/*
94 * timerlat_bpf_wait - wait until tracing is stopped or signal
95 */
96int timerlat_bpf_wait(int timeout)
97{
98 struct ring_buffer *rb;
99 int retval;
100
101 rb = ring_buffer__new(bpf_map__fd(bpf->maps.signal_stop_tracing),
102 handle_rb_event, NULL, NULL);
103 retval = ring_buffer__poll(rb, timeout * 1000);
104 ring_buffer__free(rb);
105
106 return retval;
107}
108
109/*
110 * timerlat_bpf_restart_tracing - restart stopped tracing
111 */
112int timerlat_bpf_restart_tracing(void)
113{
114 unsigned int key = 0;
115 unsigned long long value = 0;
116
117 return bpf_map__update_elem(bpf->maps.stop_tracing,
118 &key, sizeof(key),
119 &value, sizeof(value), BPF_ANY);
120}
121
122static int get_value(struct bpf_map *map_irq,
123 struct bpf_map *map_thread,
124 struct bpf_map *map_user,
125 int key,
126 long long *value_irq,
127 long long *value_thread,
128 long long *value_user,
129 int cpus)
130{
131 int err;
132
133 err = bpf_map__lookup_elem(map_irq, &key,
134 sizeof(unsigned int), value_irq,
135 sizeof(long long) * cpus, 0);
136 if (err)
137 return err;
138 err = bpf_map__lookup_elem(map_thread, &key,
139 sizeof(unsigned int), value_thread,
140 sizeof(long long) * cpus, 0);
141 if (err)
142 return err;
143 err = bpf_map__lookup_elem(map_user, &key,
144 sizeof(unsigned int), value_user,
145 sizeof(long long) * cpus, 0);
146 if (err)
147 return err;
148 return 0;
149}
150
151/*
152 * timerlat_bpf_get_hist_value - get value from BPF hist map
153 */
154int timerlat_bpf_get_hist_value(int key,
155 long long *value_irq,
156 long long *value_thread,
157 long long *value_user,
158 int cpus)
159{
160 return get_value(bpf->maps.hist_irq,
161 bpf->maps.hist_thread,
162 bpf->maps.hist_user,
163 key, value_irq, value_thread, value_user, cpus);
164}
165
166/*
167 * timerlat_bpf_get_summary_value - get value from BPF summary map
168 */
169int timerlat_bpf_get_summary_value(enum summary_field key,
170 long long *value_irq,
171 long long *value_thread,
172 long long *value_user,
173 int cpus)
174{
175 return get_value(bpf->maps.summary_irq,
176 bpf->maps.summary_thread,
177 bpf->maps.summary_user,
178 key, value_irq, value_thread, value_user, cpus);
179}
180#endif /* HAVE_BPF_SKEL */