These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / samples / bpf / trace_output_user.c

diff --git a/kernel/samples/bpf/trace_output_user.c b/kernel/samples/bpf/trace_output_user.c
new file mode 100644 (file)
index 0000000..661a7d0
--- /dev/null
+++ b/kernel/samples/bpf/trace_output_user.c
@@ -0,0 +1,196 @@
+/* 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 <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <sys/ioctl.h>
+#include <linux/perf_event.h>
+#include <linux/bpf.h>
+#include <errno.h>
+#include <assert.h>
+#include <sys/syscall.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <time.h>
+#include <signal.h>
+#include "libbpf.h"
+#include "bpf_load.h"
+
+static int pmu_fd;
+
+int page_size;
+int page_cnt = 8;
+volatile struct perf_event_mmap_page *header;
+
+typedef void (*print_fn)(void *data, int size);
+
+static int perf_event_mmap(int fd)
+{
+       void *base;
+       int mmap_size;
+
+       page_size = getpagesize();
+       mmap_size = page_size * (page_cnt + 1);
+
+       base = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+       if (base == MAP_FAILED) {
+               printf("mmap err\n");
+               return -1;
+       }
+
+       header = base;
+       return 0;
+}
+
+static int perf_event_poll(int fd)
+{
+       struct pollfd pfd = { .fd = fd, .events = POLLIN };
+
+       return poll(&pfd, 1, 1000);
+}
+
+struct perf_event_sample {
+       struct perf_event_header header;
+       __u32 size;
+       char data[];
+};
+
+void perf_event_read(print_fn fn)
+{
+       __u64 data_tail = header->data_tail;
+       __u64 data_head = header->data_head;
+       __u64 buffer_size = page_cnt * page_size;
+       void *base, *begin, *end;
+       char buf[256];
+
+       asm volatile("" ::: "memory"); /* in real code it should be smp_rmb() */
+       if (data_head == data_tail)
+               return;
+
+       base = ((char *)header) + page_size;
+
+       begin = base + data_tail % buffer_size;
+       end = base + data_head % buffer_size;
+
+       while (begin != end) {
+               struct perf_event_sample *e;
+
+               e = begin;
+               if (begin + e->header.size > base + buffer_size) {
+                       long len = base + buffer_size - begin;
+
+                       assert(len < e->header.size);
+                       memcpy(buf, begin, len);
+                       memcpy(buf + len, base, e->header.size - len);
+                       e = (void *) buf;
+                       begin = base + e->header.size - len;
+               } else if (begin + e->header.size == base + buffer_size) {
+                       begin = base;
+               } else {
+                       begin += e->header.size;
+               }
+
+               if (e->header.type == PERF_RECORD_SAMPLE) {
+                       fn(e->data, e->size);
+               } else if (e->header.type == PERF_RECORD_LOST) {
+                       struct {
+                               struct perf_event_header header;
+                               __u64 id;
+                               __u64 lost;
+                       } *lost = (void *) e;
+                       printf("lost %lld events\n", lost->lost);
+               } else {
+                       printf("unknown event type=%d size=%d\n",
+                              e->header.type, e->header.size);
+               }
+       }
+
+       __sync_synchronize(); /* smp_mb() */
+       header->data_tail = data_head;
+}
+
+static __u64 time_get_ns(void)
+{
+       struct timespec ts;
+
+       clock_gettime(CLOCK_MONOTONIC, &ts);
+       return ts.tv_sec * 1000000000ull + ts.tv_nsec;
+}
+
+static __u64 start_time;
+
+#define MAX_CNT 100000ll
+
+static void print_bpf_output(void *data, int size)
+{
+       static __u64 cnt;
+       struct {
+               __u64 pid;
+               __u64 cookie;
+       } *e = data;
+
+       if (e->cookie != 0x12345678) {
+               printf("BUG pid %llx cookie %llx sized %d\n",
+                      e->pid, e->cookie, size);
+               kill(0, SIGINT);
+       }
+
+       cnt++;
+
+       if (cnt == MAX_CNT) {
+               printf("recv %lld events per sec\n",
+                      MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
+               kill(0, SIGINT);
+       }
+}
+
+static void test_bpf_perf_event(void)
+{
+       struct perf_event_attr attr = {
+               .sample_type = PERF_SAMPLE_RAW,
+               .type = PERF_TYPE_SOFTWARE,
+               .config = PERF_COUNT_SW_BPF_OUTPUT,
+       };
+       int key = 0;
+
+       pmu_fd = perf_event_open(&attr, -1/*pid*/, 0/*cpu*/, -1/*group_fd*/, 0);
+
+       assert(pmu_fd >= 0);
+       assert(bpf_update_elem(map_fd[0], &key, &pmu_fd, BPF_ANY) == 0);
+       ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
+}
+
+int main(int argc, char **argv)
+{
+       char filename[256];
+       FILE *f;
+
+       snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+
+       if (load_bpf_file(filename)) {
+               printf("%s", bpf_log_buf);
+               return 1;
+       }
+
+       test_bpf_perf_event();
+
+       if (perf_event_mmap(pmu_fd) < 0)
+               return 1;
+
+       f = popen("taskset 1 dd if=/dev/zero of=/dev/null", "r");
+       (void) f;
+
+       start_time = time_get_ns();
+       for (;;) {
+               perf_event_poll(pmu_fd);
+               perf_event_read(print_bpf_output);
+       }
+
+       return 0;
+}