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 8 static struct timerlat_bpf *bpf; 9 10 /* 11 * timerlat_bpf_init - load and initialize BPF program to collect timerlat data 12 */ 13 int 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->output_divisor; 25 bpf->rodata->entries = params->entries; 26 bpf->rodata->irq_threshold = params->stop_us; 27 bpf->rodata->thread_threshold = params->stop_total_us; 28 bpf->rodata->aa_only = params->aa_only; 29 30 if (params->entries != 0) { 31 /* Pass histogram options */ 32 bpf->rodata->bucket_size = params->bucket_size; 33 34 /* Set histogram array sizes */ 35 bpf_map__set_max_entries(bpf->maps.hist_irq, params->entries); 36 bpf_map__set_max_entries(bpf->maps.hist_thread, params->entries); 37 bpf_map__set_max_entries(bpf->maps.hist_user, params->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->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 */ 65 int 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 */ 75 void 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 */ 83 void timerlat_bpf_destroy(void) 84 { 85 timerlat_bpf__destroy(bpf); 86 } 87 88 static 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 */ 96 int 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 */ 112 int 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 } 121 122 static 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 */ 154 int 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 */ 169 int 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 */ 181