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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /samples/bpf/sampleip_user.c | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'samples/bpf/sampleip_user.c')
-rw-r--r-- | samples/bpf/sampleip_user.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/samples/bpf/sampleip_user.c b/samples/bpf/sampleip_user.c new file mode 100644 index 000000000..921c505bb --- /dev/null +++ b/samples/bpf/sampleip_user.c @@ -0,0 +1,227 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * sampleip: sample instruction pointer and frequency count in a BPF map. + * + * Copyright 2016 Netflix, Inc. + */ +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <errno.h> +#include <signal.h> +#include <string.h> +#include <linux/perf_event.h> +#include <linux/ptrace.h> +#include <linux/bpf.h> +#include <bpf/bpf.h> +#include <bpf/libbpf.h> +#include "perf-sys.h" +#include "trace_helpers.h" + +#define DEFAULT_FREQ 99 +#define DEFAULT_SECS 5 +#define MAX_IPS 8192 +#define PAGE_OFFSET 0xffff880000000000 + +static int map_fd; +static int nr_cpus; + +static void usage(void) +{ + printf("USAGE: sampleip [-F freq] [duration]\n"); + printf(" -F freq # sample frequency (Hertz), default 99\n"); + printf(" duration # sampling duration (seconds), default 5\n"); +} + +static int sampling_start(int freq, struct bpf_program *prog, + struct bpf_link *links[]) +{ + int i, pmu_fd; + + struct perf_event_attr pe_sample_attr = { + .type = PERF_TYPE_SOFTWARE, + .freq = 1, + .sample_period = freq, + .config = PERF_COUNT_SW_CPU_CLOCK, + .inherit = 1, + }; + + for (i = 0; i < nr_cpus; i++) { + pmu_fd = sys_perf_event_open(&pe_sample_attr, -1 /* pid */, i, + -1 /* group_fd */, 0 /* flags */); + if (pmu_fd < 0) { + fprintf(stderr, "ERROR: Initializing perf sampling\n"); + return 1; + } + links[i] = bpf_program__attach_perf_event(prog, pmu_fd); + if (libbpf_get_error(links[i])) { + fprintf(stderr, "ERROR: Attach perf event\n"); + links[i] = NULL; + close(pmu_fd); + return 1; + } + } + + return 0; +} + +static void sampling_end(struct bpf_link *links[]) +{ + int i; + + for (i = 0; i < nr_cpus; i++) + bpf_link__destroy(links[i]); +} + +struct ipcount { + __u64 ip; + __u32 count; +}; + +/* used for sorting */ +struct ipcount counts[MAX_IPS]; + +static int count_cmp(const void *p1, const void *p2) +{ + return ((struct ipcount *)p1)->count - ((struct ipcount *)p2)->count; +} + +static void print_ip_map(int fd) +{ + struct ksym *sym; + __u64 key, next_key; + __u32 value; + int i, max; + + printf("%-19s %-32s %s\n", "ADDR", "KSYM", "COUNT"); + + /* fetch IPs and counts */ + key = 0, i = 0; + while (bpf_map_get_next_key(fd, &key, &next_key) == 0) { + bpf_map_lookup_elem(fd, &next_key, &value); + counts[i].ip = next_key; + counts[i++].count = value; + key = next_key; + } + max = i; + + /* sort and print */ + qsort(counts, max, sizeof(struct ipcount), count_cmp); + for (i = 0; i < max; i++) { + if (counts[i].ip > PAGE_OFFSET) { + sym = ksym_search(counts[i].ip); + if (!sym) { + printf("ksym not found. Is kallsyms loaded?\n"); + continue; + } + + printf("0x%-17llx %-32s %u\n", counts[i].ip, sym->name, + counts[i].count); + } else { + printf("0x%-17llx %-32s %u\n", counts[i].ip, "(user)", + counts[i].count); + } + } + + if (max == MAX_IPS) { + printf("WARNING: IP hash was full (max %d entries); ", max); + printf("may have dropped samples\n"); + } +} + +static void int_exit(int sig) +{ + printf("\n"); + print_ip_map(map_fd); + exit(0); +} + +int main(int argc, char **argv) +{ + int opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS, error = 1; + struct bpf_object *obj = NULL; + struct bpf_program *prog; + struct bpf_link **links; + char filename[256]; + + /* process arguments */ + while ((opt = getopt(argc, argv, "F:h")) != -1) { + switch (opt) { + case 'F': + freq = atoi(optarg); + break; + case 'h': + default: + usage(); + return 0; + } + } + if (argc - optind == 1) + secs = atoi(argv[optind]); + if (freq == 0 || secs == 0) { + usage(); + return 1; + } + + /* initialize kernel symbol translation */ + if (load_kallsyms()) { + fprintf(stderr, "ERROR: loading /proc/kallsyms\n"); + return 2; + } + + /* create perf FDs for each CPU */ + nr_cpus = sysconf(_SC_NPROCESSORS_ONLN); + links = calloc(nr_cpus, sizeof(struct bpf_link *)); + if (!links) { + fprintf(stderr, "ERROR: malloc of links\n"); + goto cleanup; + } + + snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); + obj = bpf_object__open_file(filename, NULL); + if (libbpf_get_error(obj)) { + fprintf(stderr, "ERROR: opening BPF object file failed\n"); + obj = NULL; + goto cleanup; + } + + prog = bpf_object__find_program_by_name(obj, "do_sample"); + if (!prog) { + fprintf(stderr, "ERROR: finding a prog in obj file failed\n"); + goto cleanup; + } + + /* load BPF program */ + if (bpf_object__load(obj)) { + fprintf(stderr, "ERROR: loading BPF object file failed\n"); + goto cleanup; + } + + map_fd = bpf_object__find_map_fd_by_name(obj, "ip_map"); + if (map_fd < 0) { + fprintf(stderr, "ERROR: finding a map in obj file failed\n"); + goto cleanup; + } + + signal(SIGINT, int_exit); + signal(SIGTERM, int_exit); + + /* do sampling */ + printf("Sampling at %d Hertz for %d seconds. Ctrl-C also ends.\n", + freq, secs); + if (sampling_start(freq, prog, links) != 0) + goto cleanup; + + sleep(secs); + error = 0; + +cleanup: + sampling_end(links); + /* output sample counts */ + if (!error) + print_ip_map(map_fd); + + free(links); + bpf_object__close(obj); + return error; +} |