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