From 72874418e4b9e2673c26a810b0ae9f418b573ee3 Mon Sep 17 00:00:00 2001 From: Brendan Gregg Date: Thu, 1 Sep 2016 18:37:26 -0700 Subject: samples/bpf: add sampleip example sample instruction pointer and frequency count in a BPF map Signed-off-by: Brendan Gregg Signed-off-by: Alexei Starovoitov Signed-off-by: David S. Miller --- samples/bpf/sampleip_user.c | 196 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 196 insertions(+) create mode 100644 samples/bpf/sampleip_user.c (limited to 'samples/bpf/sampleip_user.c') diff --git a/samples/bpf/sampleip_user.c b/samples/bpf/sampleip_user.c new file mode 100644 index 000000000000..260a6bdd6413 --- /dev/null +++ b/samples/bpf/sampleip_user.c @@ -0,0 +1,196 @@ +/* + * sampleip: sample instruction pointer and frequency count in a BPF map. + * + * Copyright 2016 Netflix, Inc. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "libbpf.h" +#include "bpf_load.h" + +#define DEFAULT_FREQ 99 +#define DEFAULT_SECS 5 +#define MAX_IPS 8192 +#define PAGE_OFFSET 0xffff880000000000 + +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 *pmu_fd, int freq) +{ + int i; + + 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[i] = perf_event_open(&pe_sample_attr, -1 /* pid */, i, + -1 /* group_fd */, 0 /* flags */); + if (pmu_fd[i] < 0) { + fprintf(stderr, "ERROR: Initializing perf sampling\n"); + return 1; + } + assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, + prog_fd[0]) == 0); + assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0) == 0); + } + + return 0; +} + +static void sampling_end(int *pmu_fd) +{ + int i; + + for (i = 0; i < nr_cpus; i++) + close(pmu_fd[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_get_next_key(fd, &key, &next_key) == 0) { + bpf_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); + 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[0]); + exit(0); +} + +int main(int argc, char **argv) +{ + char filename[256]; + int *pmu_fd, opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS; + + /* 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_CONF); + pmu_fd = malloc(nr_cpus * sizeof(int)); + if (pmu_fd == NULL) { + fprintf(stderr, "ERROR: malloc of pmu_fd\n"); + return 1; + } + + /* load BPF program */ + snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); + if (load_bpf_file(filename)) { + fprintf(stderr, "ERROR: loading BPF program (errno %d):\n", + errno); + if (strcmp(bpf_log_buf, "") == 0) + fprintf(stderr, "Try: ulimit -l unlimited\n"); + else + fprintf(stderr, "%s", bpf_log_buf); + return 1; + } + signal(SIGINT, int_exit); + + /* do sampling */ + printf("Sampling at %d Hertz for %d seconds. Ctrl-C also ends.\n", + freq, secs); + if (sampling_start(pmu_fd, freq) != 0) + return 1; + sleep(secs); + sampling_end(pmu_fd); + free(pmu_fd); + + /* output sample counts */ + print_ip_map(map_fd[0]); + + return 0; +} -- cgit v1.2.3