diff options
Diffstat (limited to 'collectors/ebpf.plugin/ebpf_softirq.c')
| -rw-r--r-- | collectors/ebpf.plugin/ebpf_softirq.c | 286 |
1 files changed, 286 insertions, 0 deletions
diff --git a/collectors/ebpf.plugin/ebpf_softirq.c b/collectors/ebpf.plugin/ebpf_softirq.c new file mode 100644 index 00000000..106ff4f2 --- /dev/null +++ b/collectors/ebpf.plugin/ebpf_softirq.c @@ -0,0 +1,286 @@ +// SPDX-License-Identifier: GPL-3.0-or-later + +#include "ebpf.h" +#include "ebpf_softirq.h" + +struct config softirq_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 SOFTIRQ_MAP_LATENCY 0 +static ebpf_local_maps_t softirq_maps[] = { + { + .name = "tbl_softirq", + .internal_input = NETDATA_SOFTIRQ_MAX_IRQS, + .user_input = 0, + .type = NETDATA_EBPF_MAP_STATIC, + .map_fd = ND_EBPF_MAP_FD_NOT_INITIALIZED, +#ifdef LIBBPF_MAJOR_VERSION + .map_type = BPF_MAP_TYPE_PERCPU_ARRAY +#endif + }, + /* end */ + { + .name = NULL, + .internal_input = 0, + .user_input = 0, + .type = NETDATA_EBPF_MAP_CONTROLLER, + .map_fd = ND_EBPF_MAP_FD_NOT_INITIALIZED, +#ifdef LIBBPF_MAJOR_VERSION + .map_type = BPF_MAP_TYPE_PERCPU_ARRAY +#endif + } +}; + +#define SOFTIRQ_TP_CLASS_IRQ "irq" +static ebpf_tracepoint_t softirq_tracepoints[] = { + {.enabled = false, .class = SOFTIRQ_TP_CLASS_IRQ, .event = "softirq_entry"}, + {.enabled = false, .class = SOFTIRQ_TP_CLASS_IRQ, .event = "softirq_exit"}, + /* end */ + {.enabled = false, .class = NULL, .event = NULL} +}; + +// these must be in the order defined by the kernel: +// https://elixir.bootlin.com/linux/v5.12.19/source/include/trace/events/irq.h#L13 +static softirq_val_t softirq_vals[] = { + {.name = "HI", .latency = 0}, + {.name = "TIMER", .latency = 0}, + {.name = "NET_TX", .latency = 0}, + {.name = "NET_RX", .latency = 0}, + {.name = "BLOCK", .latency = 0}, + {.name = "IRQ_POLL", .latency = 0}, + {.name = "TASKLET", .latency = 0}, + {.name = "SCHED", .latency = 0}, + {.name = "HRTIMER", .latency = 0}, + {.name = "RCU", .latency = 0}, +}; + +// tmp store for soft IRQ values we get from a per-CPU eBPF map. +static softirq_ebpf_val_t *softirq_ebpf_vals = NULL; + +/** + * Obsolete global + * + * Obsolete global charts created by thread. + * + * @param em a pointer to `struct ebpf_module` + */ +static void ebpf_obsolete_softirq_global(ebpf_module_t *em) +{ + ebpf_write_chart_obsolete(NETDATA_EBPF_SYSTEM_GROUP, + "softirq_latency", + "", + "Software IRQ latency", + EBPF_COMMON_DIMENSION_MILLISECONDS, + "softirqs", + NETDATA_EBPF_CHART_TYPE_STACKED, + NULL, + NETDATA_CHART_PRIO_SYSTEM_SOFTIRQS+1, + em->update_every); +} + +/** + * Cleanup + * + * Clean up allocated memory. + * + * @param ptr thread data. + */ +static void softirq_cleanup(void *ptr) +{ + ebpf_module_t *em = (ebpf_module_t *)ptr; + + if (em->enabled == NETDATA_THREAD_EBPF_FUNCTION_RUNNING) { + pthread_mutex_lock(&lock); + + ebpf_obsolete_softirq_global(em); + + pthread_mutex_unlock(&lock); + fflush(stdout); + } + + ebpf_update_kernel_memory_with_vector(&plugin_statistics, em->maps, EBPF_ACTION_STAT_REMOVE); + + if (em->objects) { + ebpf_unload_legacy_code(em->objects, em->probe_links); + em->objects = NULL; + em->probe_links = NULL; + } + + for (int i = 0; softirq_tracepoints[i].class != NULL; i++) { + ebpf_disable_tracepoint(&softirq_tracepoints[i]); + } + freez(softirq_ebpf_vals); + softirq_ebpf_vals = NULL; + + pthread_mutex_lock(&ebpf_exit_cleanup); + em->enabled = NETDATA_THREAD_EBPF_STOPPED; + ebpf_update_stats(&plugin_statistics, em); + pthread_mutex_unlock(&ebpf_exit_cleanup); +} + +/***************************************************************** + * MAIN LOOP + *****************************************************************/ + +/** + * Read Latency Map + * + * Read data from kernel ring to plot for users. + * + * @param maps_per_core do I need to read all cores? + */ +static void softirq_read_latency_map(int maps_per_core) +{ + int fd = softirq_maps[SOFTIRQ_MAP_LATENCY].map_fd; + int i; + size_t length = sizeof(softirq_ebpf_val_t); + if (maps_per_core) + length *= ebpf_nprocs; + + for (i = 0; i < NETDATA_SOFTIRQ_MAX_IRQS; i++) { + int test = bpf_map_lookup_elem(fd, &i, softirq_ebpf_vals); + if (unlikely(test < 0)) { + continue; + } + + uint64_t total_latency = 0; + int cpu_i; + int end = (maps_per_core) ? ebpf_nprocs : 1; + for (cpu_i = 0; cpu_i < end; cpu_i++) { + total_latency += softirq_ebpf_vals[cpu_i].latency/1000; + } + + softirq_vals[i].latency = total_latency; + memset(softirq_ebpf_vals, 0, length); + } +} + +static void softirq_create_charts(int update_every) +{ + ebpf_create_chart( + NETDATA_EBPF_SYSTEM_GROUP, + "softirq_latency", + "Software IRQ latency", + EBPF_COMMON_DIMENSION_MILLISECONDS, + "softirqs", + NULL, + NETDATA_EBPF_CHART_TYPE_STACKED, + NETDATA_CHART_PRIO_SYSTEM_SOFTIRQS+1, + NULL, NULL, 0, update_every, + NETDATA_EBPF_MODULE_NAME_SOFTIRQ + ); + + fflush(stdout); +} + +static void softirq_create_dims() +{ + uint32_t i; + for (i = 0; i < NETDATA_SOFTIRQ_MAX_IRQS; i++) { + ebpf_write_global_dimension( + softirq_vals[i].name, softirq_vals[i].name, + ebpf_algorithms[NETDATA_EBPF_INCREMENTAL_IDX] + ); + } +} + +static inline void softirq_write_dims() +{ + uint32_t i; + for (i = 0; i < NETDATA_SOFTIRQ_MAX_IRQS; i++) { + write_chart_dimension(softirq_vals[i].name, softirq_vals[i].latency); + } +} + +/** +* Main loop for this collector. +*/ +static void softirq_collector(ebpf_module_t *em) +{ + softirq_ebpf_vals = callocz(ebpf_nprocs, sizeof(softirq_ebpf_val_t)); + + // create chart and static dims. + pthread_mutex_lock(&lock); + softirq_create_charts(em->update_every); + softirq_create_dims(); + ebpf_update_stats(&plugin_statistics, em); + ebpf_update_kernel_memory_with_vector(&plugin_statistics, em->maps, EBPF_ACTION_STAT_ADD); + pthread_mutex_unlock(&lock); + + // loop and read from published data until ebpf plugin is closed. + heartbeat_t hb; + heartbeat_init(&hb); + int update_every = em->update_every; + int counter = update_every - 1; + int maps_per_core = em->maps_per_core; + //This will be cancelled by its parent + uint32_t running_time = 0; + uint32_t lifetime = em->lifetime; + while (!ebpf_plugin_exit && running_time < lifetime) { + (void)heartbeat_next(&hb, USEC_PER_SEC); + if (ebpf_plugin_exit || ++counter != update_every) + continue; + + counter = 0; + softirq_read_latency_map(maps_per_core); + pthread_mutex_lock(&lock); + + // write dims now for all hitherto discovered IRQs. + ebpf_write_begin_chart(NETDATA_EBPF_SYSTEM_GROUP, "softirq_latency", ""); + softirq_write_dims(); + ebpf_write_end_chart(); + + pthread_mutex_unlock(&lock); + + pthread_mutex_lock(&ebpf_exit_cleanup); + if (running_time && !em->running_time) + running_time = update_every; + else + running_time += update_every; + + em->running_time = running_time; + pthread_mutex_unlock(&ebpf_exit_cleanup); + } +} + +/***************************************************************** + * EBPF SOFTIRQ THREAD + *****************************************************************/ + +/** + * Soft IRQ latency thread. + * + * @param ptr a `ebpf_module_t *`. + * @return always NULL. + */ +void *ebpf_softirq_thread(void *ptr) +{ + netdata_thread_cleanup_push(softirq_cleanup, ptr); + + ebpf_module_t *em = (ebpf_module_t *)ptr; + em->maps = softirq_maps; + + if (ebpf_enable_tracepoints(softirq_tracepoints) == 0) { + goto endsoftirq; + } + +#ifdef LIBBPF_MAJOR_VERSION + ebpf_define_map_type(em->maps, em->maps_per_core, running_on_kernel); +#endif + em->probe_links = ebpf_load_program(ebpf_plugin_dir, em, running_on_kernel, isrh, &em->objects); + if (!em->probe_links) { + goto endsoftirq; + } + + softirq_collector(em); + +endsoftirq: + ebpf_update_disabled_plugin_stats(em); + + netdata_thread_cleanup_pop(1); + + return NULL; +} |