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227 lines
4.8 KiB
227 lines
4.8 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* sampleip: sample instruction pointer and frequency count in a BPF map. |
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* |
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* Copyright 2016 Netflix, Inc. |
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*/ |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <unistd.h> |
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#include <errno.h> |
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#include <signal.h> |
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#include <string.h> |
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#include <linux/perf_event.h> |
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#include <linux/ptrace.h> |
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#include <linux/bpf.h> |
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#include <bpf/bpf.h> |
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#include <bpf/libbpf.h> |
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#include "perf-sys.h" |
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#include "trace_helpers.h" |
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#define DEFAULT_FREQ 99 |
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#define DEFAULT_SECS 5 |
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#define MAX_IPS 8192 |
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#define PAGE_OFFSET 0xffff880000000000 |
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static int map_fd; |
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static int nr_cpus; |
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static void usage(void) |
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{ |
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printf("USAGE: sampleip [-F freq] [duration]\n"); |
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printf(" -F freq # sample frequency (Hertz), default 99\n"); |
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printf(" duration # sampling duration (seconds), default 5\n"); |
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} |
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static int sampling_start(int freq, struct bpf_program *prog, |
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struct bpf_link *links[]) |
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{ |
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int i, pmu_fd; |
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struct perf_event_attr pe_sample_attr = { |
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.type = PERF_TYPE_SOFTWARE, |
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.freq = 1, |
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.sample_period = freq, |
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.config = PERF_COUNT_SW_CPU_CLOCK, |
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.inherit = 1, |
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}; |
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for (i = 0; i < nr_cpus; i++) { |
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pmu_fd = sys_perf_event_open(&pe_sample_attr, -1 /* pid */, i, |
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-1 /* group_fd */, 0 /* flags */); |
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if (pmu_fd < 0) { |
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fprintf(stderr, "ERROR: Initializing perf sampling\n"); |
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return 1; |
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} |
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links[i] = bpf_program__attach_perf_event(prog, pmu_fd); |
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if (libbpf_get_error(links[i])) { |
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fprintf(stderr, "ERROR: Attach perf event\n"); |
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links[i] = NULL; |
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close(pmu_fd); |
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return 1; |
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} |
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} |
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return 0; |
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} |
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static void sampling_end(struct bpf_link *links[]) |
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{ |
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int i; |
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for (i = 0; i < nr_cpus; i++) |
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bpf_link__destroy(links[i]); |
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} |
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struct ipcount { |
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__u64 ip; |
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__u32 count; |
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}; |
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/* used for sorting */ |
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struct ipcount counts[MAX_IPS]; |
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static int count_cmp(const void *p1, const void *p2) |
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{ |
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return ((struct ipcount *)p1)->count - ((struct ipcount *)p2)->count; |
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} |
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static void print_ip_map(int fd) |
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{ |
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struct ksym *sym; |
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__u64 key, next_key; |
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__u32 value; |
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int i, max; |
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printf("%-19s %-32s %s\n", "ADDR", "KSYM", "COUNT"); |
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/* fetch IPs and counts */ |
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key = 0, i = 0; |
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while (bpf_map_get_next_key(fd, &key, &next_key) == 0) { |
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bpf_map_lookup_elem(fd, &next_key, &value); |
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counts[i].ip = next_key; |
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counts[i++].count = value; |
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key = next_key; |
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} |
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max = i; |
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/* sort and print */ |
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qsort(counts, max, sizeof(struct ipcount), count_cmp); |
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for (i = 0; i < max; i++) { |
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if (counts[i].ip > PAGE_OFFSET) { |
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sym = ksym_search(counts[i].ip); |
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if (!sym) { |
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printf("ksym not found. Is kallsyms loaded?\n"); |
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continue; |
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} |
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printf("0x%-17llx %-32s %u\n", counts[i].ip, sym->name, |
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counts[i].count); |
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} else { |
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printf("0x%-17llx %-32s %u\n", counts[i].ip, "(user)", |
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counts[i].count); |
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} |
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} |
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if (max == MAX_IPS) { |
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printf("WARNING: IP hash was full (max %d entries); ", max); |
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printf("may have dropped samples\n"); |
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} |
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} |
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static void int_exit(int sig) |
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{ |
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printf("\n"); |
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print_ip_map(map_fd); |
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exit(0); |
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} |
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int main(int argc, char **argv) |
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{ |
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int opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS, error = 1; |
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struct bpf_object *obj = NULL; |
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struct bpf_program *prog; |
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struct bpf_link **links; |
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char filename[256]; |
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/* process arguments */ |
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while ((opt = getopt(argc, argv, "F:h")) != -1) { |
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switch (opt) { |
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case 'F': |
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freq = atoi(optarg); |
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break; |
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case 'h': |
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default: |
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usage(); |
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return 0; |
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} |
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} |
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if (argc - optind == 1) |
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secs = atoi(argv[optind]); |
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if (freq == 0 || secs == 0) { |
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usage(); |
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return 1; |
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} |
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/* initialize kernel symbol translation */ |
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if (load_kallsyms()) { |
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fprintf(stderr, "ERROR: loading /proc/kallsyms\n"); |
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return 2; |
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} |
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/* create perf FDs for each CPU */ |
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nr_cpus = sysconf(_SC_NPROCESSORS_ONLN); |
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links = calloc(nr_cpus, sizeof(struct bpf_link *)); |
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if (!links) { |
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fprintf(stderr, "ERROR: malloc of links\n"); |
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goto cleanup; |
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} |
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snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); |
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obj = bpf_object__open_file(filename, NULL); |
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if (libbpf_get_error(obj)) { |
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fprintf(stderr, "ERROR: opening BPF object file failed\n"); |
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obj = NULL; |
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goto cleanup; |
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} |
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prog = bpf_object__find_program_by_name(obj, "do_sample"); |
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if (!prog) { |
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fprintf(stderr, "ERROR: finding a prog in obj file failed\n"); |
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goto cleanup; |
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} |
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/* load BPF program */ |
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if (bpf_object__load(obj)) { |
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fprintf(stderr, "ERROR: loading BPF object file failed\n"); |
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goto cleanup; |
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} |
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map_fd = bpf_object__find_map_fd_by_name(obj, "ip_map"); |
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if (map_fd < 0) { |
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fprintf(stderr, "ERROR: finding a map in obj file failed\n"); |
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goto cleanup; |
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} |
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signal(SIGINT, int_exit); |
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signal(SIGTERM, int_exit); |
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/* do sampling */ |
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printf("Sampling at %d Hertz for %d seconds. Ctrl-C also ends.\n", |
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freq, secs); |
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if (sampling_start(freq, prog, links) != 0) |
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goto cleanup; |
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sleep(secs); |
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error = 0; |
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cleanup: |
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sampling_end(links); |
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/* output sample counts */ |
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if (!error) |
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print_ip_map(map_fd); |
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free(links); |
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bpf_object__close(obj); |
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return error; |
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}
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