2015-10-21 05:02:35 +02:00
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/* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*/
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#include <stdio.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <stdbool.h>
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#include <string.h>
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#include <fcntl.h>
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#include <poll.h>
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#include <linux/perf_event.h>
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#include <linux/bpf.h>
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#include <errno.h>
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#include <assert.h>
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#include <sys/syscall.h>
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#include <sys/ioctl.h>
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#include <sys/mman.h>
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#include <time.h>
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#include <signal.h>
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#include "libbpf.h"
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#include "bpf_load.h"
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2016-12-09 03:46:19 +01:00
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#include "perf-sys.h"
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2015-10-21 05:02:35 +02:00
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static int pmu_fd;
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int page_size;
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int page_cnt = 8;
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volatile struct perf_event_mmap_page *header;
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typedef void (*print_fn)(void *data, int size);
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static int perf_event_mmap(int fd)
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{
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void *base;
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int mmap_size;
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page_size = getpagesize();
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mmap_size = page_size * (page_cnt + 1);
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base = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
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if (base == MAP_FAILED) {
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printf("mmap err\n");
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return -1;
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}
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header = base;
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return 0;
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}
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static int perf_event_poll(int fd)
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{
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struct pollfd pfd = { .fd = fd, .events = POLLIN };
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return poll(&pfd, 1, 1000);
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}
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struct perf_event_sample {
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struct perf_event_header header;
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__u32 size;
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char data[];
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};
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2016-12-15 16:29:27 +01:00
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static void perf_event_read(print_fn fn)
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2015-10-21 05:02:35 +02:00
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{
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__u64 data_tail = header->data_tail;
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__u64 data_head = header->data_head;
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__u64 buffer_size = page_cnt * page_size;
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void *base, *begin, *end;
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char buf[256];
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asm volatile("" ::: "memory"); /* in real code it should be smp_rmb() */
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if (data_head == data_tail)
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return;
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base = ((char *)header) + page_size;
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begin = base + data_tail % buffer_size;
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end = base + data_head % buffer_size;
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while (begin != end) {
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struct perf_event_sample *e;
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e = begin;
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if (begin + e->header.size > base + buffer_size) {
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long len = base + buffer_size - begin;
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assert(len < e->header.size);
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memcpy(buf, begin, len);
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memcpy(buf + len, base, e->header.size - len);
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e = (void *) buf;
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begin = base + e->header.size - len;
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} else if (begin + e->header.size == base + buffer_size) {
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begin = base;
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} else {
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begin += e->header.size;
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}
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if (e->header.type == PERF_RECORD_SAMPLE) {
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fn(e->data, e->size);
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} else if (e->header.type == PERF_RECORD_LOST) {
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struct {
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struct perf_event_header header;
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__u64 id;
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__u64 lost;
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} *lost = (void *) e;
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printf("lost %lld events\n", lost->lost);
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} else {
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printf("unknown event type=%d size=%d\n",
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e->header.type, e->header.size);
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}
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}
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__sync_synchronize(); /* smp_mb() */
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header->data_tail = data_head;
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}
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static __u64 time_get_ns(void)
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{
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struct timespec ts;
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clock_gettime(CLOCK_MONOTONIC, &ts);
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return ts.tv_sec * 1000000000ull + ts.tv_nsec;
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}
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static __u64 start_time;
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#define MAX_CNT 100000ll
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static void print_bpf_output(void *data, int size)
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{
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static __u64 cnt;
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struct {
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__u64 pid;
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__u64 cookie;
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} *e = data;
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if (e->cookie != 0x12345678) {
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printf("BUG pid %llx cookie %llx sized %d\n",
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e->pid, e->cookie, size);
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kill(0, SIGINT);
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}
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cnt++;
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if (cnt == MAX_CNT) {
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printf("recv %lld events per sec\n",
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MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
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kill(0, SIGINT);
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}
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}
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static void test_bpf_perf_event(void)
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{
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struct perf_event_attr attr = {
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.sample_type = PERF_SAMPLE_RAW,
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.type = PERF_TYPE_SOFTWARE,
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.config = PERF_COUNT_SW_BPF_OUTPUT,
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};
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int key = 0;
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2016-12-09 03:46:19 +01:00
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pmu_fd = sys_perf_event_open(&attr, -1/*pid*/, 0/*cpu*/, -1/*group_fd*/, 0);
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2015-10-21 05:02:35 +02:00
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assert(pmu_fd >= 0);
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samples/bpf: Make samples more libbpf-centric
Switch all of the sample code to use the function names from
tools/lib/bpf so that they're consistent with that, and to declare their
own log buffers. This allow the next commit to be purely devoted to
getting rid of the duplicate library in samples/bpf.
Committer notes:
Testing it:
On a fedora rawhide container, with clang/llvm 3.9, sharing the host
linux kernel git tree:
# make O=/tmp/build/linux/ headers_install
# make O=/tmp/build/linux -C samples/bpf/
Since I forgot to make it privileged, just tested it outside the
container, using what it generated:
# uname -a
Linux jouet 4.9.0-rc8+ #1 SMP Mon Dec 12 11:20:49 BRT 2016 x86_64 x86_64 x86_64 GNU/Linux
# cd /var/lib/docker/devicemapper/mnt/c43e09a53ff56c86a07baf79847f00e2cc2a17a1e2220e1adbf8cbc62734feda/rootfs/tmp/build/linux/samples/bpf/
# ls -la offwaketime
-rwxr-xr-x. 1 root root 24200 Dec 15 12:19 offwaketime
# file offwaketime
offwaketime: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=c940d3f127d5e66cdd680e42d885cb0b64f8a0e4, not stripped
# readelf -SW offwaketime_kern.o | grep PROGBITS
[ 2] .text PROGBITS 0000000000000000 000040 000000 00 AX 0 0 4
[ 3] kprobe/try_to_wake_up PROGBITS 0000000000000000 000040 0000d8 00 AX 0 0 8
[ 5] tracepoint/sched/sched_switch PROGBITS 0000000000000000 000118 000318 00 AX 0 0 8
[ 7] maps PROGBITS 0000000000000000 000430 000050 00 WA 0 0 4
[ 8] license PROGBITS 0000000000000000 000480 000004 00 WA 0 0 1
[ 9] version PROGBITS 0000000000000000 000484 000004 00 WA 0 0 4
# ./offwaketime | head -5
swapper/1;start_secondary;cpu_startup_entry;schedule_preempt_disabled;schedule;__schedule;-;---;; 106
CPU 0/KVM;entry_SYSCALL_64_fastpath;sys_ioctl;do_vfs_ioctl;kvm_vcpu_ioctl;kvm_arch_vcpu_ioctl_run;kvm_vcpu_block;schedule;__schedule;-;try_to_wake_up;swake_up_locked;swake_up;apic_timer_expired;apic_timer_fn;__hrtimer_run_queues;hrtimer_interrupt;local_apic_timer_interrupt;smp_apic_timer_interrupt;__irqentry_text_start;cpuidle_enter;call_cpuidle;cpu_startup_entry;start_secondary;;swapper/3 2
Compositor;entry_SYSCALL_64_fastpath;sys_futex;do_futex;futex_wait;futex_wait_queue_me;schedule;__schedule;-;try_to_wake_up;futex_requeue;do_futex;sys_futex;entry_SYSCALL_64_fastpath;;SoftwareVsyncTh 5
firefox;entry_SYSCALL_64_fastpath;sys_poll;do_sys_poll;poll_schedule_timeout;schedule_hrtimeout_range;schedule_hrtimeout_range_clock;schedule;__schedule;-;try_to_wake_up;pollwake;__wake_up_common;__wake_up_sync_key;pipe_write;__vfs_write;vfs_write;sys_write;entry_SYSCALL_64_fastpath;;Timer 13
JS Helper;entry_SYSCALL_64_fastpath;sys_futex;do_futex;futex_wait;futex_wait_queue_me;schedule;__schedule;-;try_to_wake_up;do_futex;sys_futex;entry_SYSCALL_64_fastpath;;firefox 2
#
Signed-off-by: Joe Stringer <joe@ovn.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20161214224342.12858-2-joe@ovn.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-12-14 23:43:38 +01:00
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assert(bpf_map_update_elem(map_fd[0], &key, &pmu_fd, BPF_ANY) == 0);
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2015-10-21 05:02:35 +02:00
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ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
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}
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int main(int argc, char **argv)
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{
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char filename[256];
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FILE *f;
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snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
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if (load_bpf_file(filename)) {
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printf("%s", bpf_log_buf);
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return 1;
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}
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test_bpf_perf_event();
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if (perf_event_mmap(pmu_fd) < 0)
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return 1;
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f = popen("taskset 1 dd if=/dev/zero of=/dev/null", "r");
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(void) f;
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start_time = time_get_ns();
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for (;;) {
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perf_event_poll(pmu_fd);
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perf_event_read(print_bpf_output);
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}
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return 0;
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}
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