diff options
Diffstat (limited to 'collectors/ebpf.plugin/ebpf_hardirq.c')
| -rw-r--r-- | collectors/ebpf.plugin/ebpf_hardirq.c | 494 |
1 files changed, 494 insertions, 0 deletions
diff --git a/collectors/ebpf.plugin/ebpf_hardirq.c b/collectors/ebpf.plugin/ebpf_hardirq.c new file mode 100644 index 000000000..ff649e9cd --- /dev/null +++ b/collectors/ebpf.plugin/ebpf_hardirq.c @@ -0,0 +1,494 @@ +// SPDX-License-Identifier: GPL-3.0-or-later + +#include "ebpf.h" +#include "ebpf_hardirq.h" + +struct config hardirq_config = { .first_section = NULL, + .last_section = NULL, + .mutex = NETDATA_MUTEX_INITIALIZER, + .index = { .avl_tree = { .root = NULL, .compar = appconfig_section_compare }, + .rwlock = AVL_LOCK_INITIALIZER } }; + +#define HARDIRQ_MAP_LATENCY 0 +#define HARDIRQ_MAP_LATENCY_STATIC 1 +static ebpf_local_maps_t hardirq_maps[] = { + { + .name = "tbl_hardirq", + .internal_input = NETDATA_HARDIRQ_MAX_IRQS, + .user_input = 0, + .type = NETDATA_EBPF_MAP_STATIC, + .map_fd = ND_EBPF_MAP_FD_NOT_INITIALIZED + }, + { + .name = "tbl_hardirq_static", + .internal_input = HARDIRQ_EBPF_STATIC_END, + .user_input = 0, + .type = NETDATA_EBPF_MAP_STATIC, + .map_fd = ND_EBPF_MAP_FD_NOT_INITIALIZED + }, + /* end */ + { + .name = NULL, + .internal_input = 0, + .user_input = 0, + .type = NETDATA_EBPF_MAP_CONTROLLER, + .map_fd = ND_EBPF_MAP_FD_NOT_INITIALIZED + } +}; + +#define HARDIRQ_TP_CLASS_IRQ "irq" +#define HARDIRQ_TP_CLASS_IRQ_VECTORS "irq_vectors" +static ebpf_tracepoint_t hardirq_tracepoints[] = { + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ, .event = "irq_handler_entry"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ, .event = "irq_handler_exit"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "thermal_apic_entry"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "thermal_apic_exit"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "threshold_apic_entry"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "threshold_apic_exit"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "error_apic_entry"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "error_apic_exit"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "deferred_error_apic_entry"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "deferred_error_apic_exit"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "spurious_apic_entry"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "spurious_apic_exit"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "call_function_entry"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "call_function_exit"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "call_function_single_entry"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "call_function_single_exit"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "reschedule_entry"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "reschedule_exit"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "local_timer_entry"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "local_timer_exit"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "irq_work_entry"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "irq_work_exit"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "x86_platform_ipi_entry"}, + {.enabled = false, .class = HARDIRQ_TP_CLASS_IRQ_VECTORS, .event = "x86_platform_ipi_exit"}, + /* end */ + {.enabled = false, .class = NULL, .event = NULL} +}; + +static hardirq_static_val_t hardirq_static_vals[] = { + { + .idx = HARDIRQ_EBPF_STATIC_APIC_THERMAL, + .name = "apic_thermal", + .latency = 0 + }, + { + .idx = HARDIRQ_EBPF_STATIC_APIC_THRESHOLD, + .name = "apic_threshold", + .latency = 0 + }, + { + .idx = HARDIRQ_EBPF_STATIC_APIC_ERROR, + .name = "apic_error", + .latency = 0 + }, + { + .idx = HARDIRQ_EBPF_STATIC_APIC_DEFERRED_ERROR, + .name = "apic_deferred_error", + .latency = 0 + }, + { + .idx = HARDIRQ_EBPF_STATIC_APIC_SPURIOUS, + .name = "apic_spurious", + .latency = 0 + }, + { + .idx = HARDIRQ_EBPF_STATIC_FUNC_CALL, + .name = "func_call", + .latency = 0 + }, + { + .idx = HARDIRQ_EBPF_STATIC_FUNC_CALL_SINGLE, + .name = "func_call_single", + .latency = 0 + }, + { + .idx = HARDIRQ_EBPF_STATIC_RESCHEDULE, + .name = "reschedule", + .latency = 0 + }, + { + .idx = HARDIRQ_EBPF_STATIC_LOCAL_TIMER, + .name = "local_timer", + .latency = 0 + }, + { + .idx = HARDIRQ_EBPF_STATIC_IRQ_WORK, + .name = "irq_work", + .latency = 0 + }, + { + .idx = HARDIRQ_EBPF_STATIC_X86_PLATFORM_IPI, + .name = "x86_platform_ipi", + .latency = 0 + }, +}; + +static struct bpf_link **probe_links = NULL; +static struct bpf_object *objects = NULL; + +static int read_thread_closed = 1; + +// store for "published" data from the reader thread, which the collector +// thread will write to netdata agent. +static avl_tree_lock hardirq_pub; + +// tmp store for dynamic hard IRQ values we get from a per-CPU eBPF map. +static hardirq_ebpf_val_t *hardirq_ebpf_vals = NULL; + +// tmp store for static hard IRQ values we get from a per-CPU eBPF map. +static hardirq_ebpf_static_val_t *hardirq_ebpf_static_vals = NULL; + +static struct netdata_static_thread hardirq_threads = {"HARDIRQ KERNEL", + NULL, NULL, 1, NULL, + NULL, NULL }; + +/** + * Clean up the main thread. + * + * @param ptr thread data. + */ +static void hardirq_cleanup(void *ptr) +{ + for (int i = 0; hardirq_tracepoints[i].class != NULL; i++) { + ebpf_disable_tracepoint(&hardirq_tracepoints[i]); + } + + ebpf_module_t *em = (ebpf_module_t *)ptr; + if (!em->enabled) { + return; + } + + heartbeat_t hb; + heartbeat_init(&hb); + uint32_t tick = 1 * USEC_PER_MS; + while (!read_thread_closed) { + usec_t dt = heartbeat_next(&hb, tick); + UNUSED(dt); + } + + freez(hardirq_ebpf_vals); + freez(hardirq_ebpf_static_vals); + freez(hardirq_threads.thread); + + if (probe_links) { + struct bpf_program *prog; + size_t i = 0 ; + bpf_object__for_each_program(prog, objects) { + bpf_link__destroy(probe_links[i]); + i++; + } + bpf_object__close(objects); + } +} + +/***************************************************************** + * MAIN LOOP + *****************************************************************/ + +/** + * Compare hard IRQ values. + * + * @param a `hardirq_val_t *`. + * @param b `hardirq_val_t *`. + * + * @return 0 if a==b, 1 if a>b, -1 if a<b. +*/ +static int hardirq_val_cmp(void *a, void *b) +{ + hardirq_val_t *ptr1 = a; + hardirq_val_t *ptr2 = b; + + if (ptr1->irq > ptr2->irq) { + return 1; + } + else if (ptr1->irq < ptr2->irq) { + return -1; + } + else { + return 0; + } +} + +static void hardirq_read_latency_map(int mapfd) +{ + hardirq_ebpf_key_t key = {}; + hardirq_ebpf_key_t next_key = {}; + hardirq_val_t search_v = {}; + hardirq_val_t *v = NULL; + + while (bpf_map_get_next_key(mapfd, &key, &next_key) == 0) { + // get val for this key. + int test = bpf_map_lookup_elem(mapfd, &key, hardirq_ebpf_vals); + if (unlikely(test < 0)) { + key = next_key; + continue; + } + + // is this IRQ saved yet? + // + // if not, make a new one, mark it as unsaved for now, and continue; we + // will insert it at the end after all of its values are correctly set, + // so that we can safely publish it to the collector within a single, + // short locked operation. + // + // otherwise simply continue; we will only update the latency, which + // can be republished safely without a lock. + // + // NOTE: lock isn't strictly necessary for this initial search, as only + // this thread does writing, but the AVL is using a read-write lock so + // there is no congestion. + bool v_is_new = false; + search_v.irq = key.irq; + v = (hardirq_val_t *)avl_search_lock(&hardirq_pub, (avl_t *)&search_v); + if (unlikely(v == NULL)) { + // latency/name can only be added reliably at a later time. + // when they're added, only then will we AVL insert. + v = callocz(1, sizeof(hardirq_val_t)); + v->irq = key.irq; + v->dim_exists = false; + + v_is_new = true; + } + + // note two things: + // 1. we must add up latency value for this IRQ across all CPUs. + // 2. the name is unfortunately *not* available on all CPU maps - only + // a single map contains the name, so we must find it. we only need + // to copy it though if the IRQ is new for us. + bool name_saved = false; + uint64_t total_latency = 0; + int i; + int end = (running_on_kernel < NETDATA_KERNEL_V4_15) ? 1 : ebpf_nprocs; + for (i = 0; i < end; i++) { + total_latency += hardirq_ebpf_vals[i].latency/1000; + + // copy name for new IRQs. + if (v_is_new && !name_saved && hardirq_ebpf_vals[i].name[0] != '\0') { + strncpyz( + v->name, + hardirq_ebpf_vals[i].name, + NETDATA_HARDIRQ_NAME_LEN + ); + name_saved = true; + } + } + + // can now safely publish latency for existing IRQs. + v->latency = total_latency; + + // can now safely publish new IRQ. + if (v_is_new) { + avl_t *check = avl_insert_lock(&hardirq_pub, (avl_t *)v); + if (check != (avl_t *)v) { + error("Internal error, cannot insert the AVL tree."); + } + } + + key = next_key; + } +} + +static void hardirq_read_latency_static_map(int mapfd) +{ + uint32_t i; + for (i = 0; i < HARDIRQ_EBPF_STATIC_END; i++) { + uint32_t map_i = hardirq_static_vals[i].idx; + int test = bpf_map_lookup_elem(mapfd, &map_i, hardirq_ebpf_static_vals); + if (unlikely(test < 0)) { + continue; + } + + uint64_t total_latency = 0; + int cpu_i; + int end = (running_on_kernel < NETDATA_KERNEL_V4_15) ? 1 : ebpf_nprocs; + for (cpu_i = 0; cpu_i < end; cpu_i++) { + total_latency += hardirq_ebpf_static_vals[cpu_i].latency/1000; + } + + hardirq_static_vals[i].latency = total_latency; + } +} + +/** + * Read eBPF maps for hard IRQ. + */ +static void *hardirq_reader(void *ptr) +{ + read_thread_closed = 0; + + heartbeat_t hb; + heartbeat_init(&hb); + + ebpf_module_t *em = (ebpf_module_t *)ptr; + + usec_t step = NETDATA_HARDIRQ_SLEEP_MS * em->update_every; + while (!close_ebpf_plugin) { + usec_t dt = heartbeat_next(&hb, step); + UNUSED(dt); + + hardirq_read_latency_map(hardirq_maps[HARDIRQ_MAP_LATENCY].map_fd); + hardirq_read_latency_static_map(hardirq_maps[HARDIRQ_MAP_LATENCY_STATIC].map_fd); + } + + read_thread_closed = 1; + return NULL; +} + +static void hardirq_create_charts(int update_every) +{ + ebpf_create_chart( + NETDATA_EBPF_SYSTEM_GROUP, + "hardirq_latency", + "Hardware IRQ latency", + EBPF_COMMON_DIMENSION_MILLISECONDS, + "interrupts", + NULL, + NETDATA_EBPF_CHART_TYPE_STACKED, + NETDATA_CHART_PRIO_HARDIRQ_LATENCY, + NULL, NULL, 0, update_every, + NETDATA_EBPF_MODULE_NAME_HARDIRQ + ); + + fflush(stdout); +} + +static void hardirq_create_static_dims() +{ + uint32_t i; + for (i = 0; i < HARDIRQ_EBPF_STATIC_END; i++) { + ebpf_write_global_dimension( + hardirq_static_vals[i].name, hardirq_static_vals[i].name, + ebpf_algorithms[NETDATA_EBPF_INCREMENTAL_IDX] + ); + } +} + +// callback for avl tree traversal on `hardirq_pub`. +static int hardirq_write_dims(void *entry, void *data) +{ + UNUSED(data); + + hardirq_val_t *v = entry; + + // IRQs get dynamically added in, so add the dimension if we haven't yet. + if (!v->dim_exists) { + ebpf_write_global_dimension( + v->name, v->name, + ebpf_algorithms[NETDATA_EBPF_INCREMENTAL_IDX] + ); + v->dim_exists = true; + } + + write_chart_dimension(v->name, v->latency); + + return 1; +} + +static inline void hardirq_write_static_dims() +{ + uint32_t i; + for (i = 0; i < HARDIRQ_EBPF_STATIC_END; i++) { + write_chart_dimension( + hardirq_static_vals[i].name, + hardirq_static_vals[i].latency + ); + } +} + +/** +* Main loop for this collector. +*/ +static void hardirq_collector(ebpf_module_t *em) +{ + hardirq_ebpf_vals = callocz( + (running_on_kernel < NETDATA_KERNEL_V4_15) ? 1 : ebpf_nprocs, + sizeof(hardirq_ebpf_val_t) + ); + hardirq_ebpf_static_vals = callocz( + (running_on_kernel < NETDATA_KERNEL_V4_15) ? 1 : ebpf_nprocs, + sizeof(hardirq_ebpf_static_val_t) + ); + + avl_init_lock(&hardirq_pub, hardirq_val_cmp); + + // create reader thread. + hardirq_threads.thread = mallocz(sizeof(netdata_thread_t)); + hardirq_threads.start_routine = hardirq_reader; + netdata_thread_create( + hardirq_threads.thread, + hardirq_threads.name, + NETDATA_THREAD_OPTION_JOINABLE, + hardirq_reader, + em + ); + + // create chart and static dims. + pthread_mutex_lock(&lock); + hardirq_create_charts(em->update_every); + hardirq_create_static_dims(); + pthread_mutex_unlock(&lock); + + // loop and read from published data until ebpf plugin is closed. + int update_every = em->update_every; + int counter = update_every - 1; + while (!close_ebpf_plugin) { + pthread_mutex_lock(&collect_data_mutex); + pthread_cond_wait(&collect_data_cond_var, &collect_data_mutex); + + if (++counter == update_every) { + counter = 0; + pthread_mutex_lock(&lock); + + // write dims now for all hitherto discovered IRQs. + write_begin_chart(NETDATA_EBPF_SYSTEM_GROUP, "hardirq_latency"); + avl_traverse_lock(&hardirq_pub, hardirq_write_dims, NULL); + hardirq_write_static_dims(); + write_end_chart(); + + pthread_mutex_unlock(&lock); + } + + pthread_mutex_unlock(&collect_data_mutex); + } +} + +/***************************************************************** + * EBPF HARDIRQ THREAD + *****************************************************************/ + +/** + * Hard IRQ latency thread. + * + * @param ptr a `ebpf_module_t *`. + * @return always NULL. + */ +void *ebpf_hardirq_thread(void *ptr) +{ + netdata_thread_cleanup_push(hardirq_cleanup, ptr); + + ebpf_module_t *em = (ebpf_module_t *)ptr; + em->maps = hardirq_maps; + + if (!em->enabled) { + goto endhardirq; + } + + if (ebpf_enable_tracepoints(hardirq_tracepoints) == 0) { + em->enabled = CONFIG_BOOLEAN_NO; + goto endhardirq; + } + + probe_links = ebpf_load_program(ebpf_plugin_dir, em, kernel_string, &objects); + if (!probe_links) { + goto endhardirq; + } + + hardirq_collector(em); + +endhardirq: + netdata_thread_cleanup_pop(1); + + return NULL; +} |