diff options
| author | Ingo Molnar <[email protected]> | 2016-10-16 11:31:39 +0200 |
|---|---|---|
| committer | Ingo Molnar <[email protected]> | 2016-10-16 11:31:39 +0200 |
| commit | 1d33369db25eb7f37b7a8bd22d736888b4501a9c (patch) | |
| tree | 116d764339be1bca928870151decbedc53a9e1d1 /samples/bpf/trace_event_kern.c | |
| parent | 23446cb66c073b827779e5eb3dec301623299b32 (diff) | |
| parent | 1001354ca34179f3db924eb66672442a173147dc (diff) | |
Merge tag 'v4.9-rc1' into x86/urgent, to pick up updates
Signed-off-by: Ingo Molnar <[email protected]>
Diffstat (limited to 'samples/bpf/trace_event_kern.c')
| -rw-r--r-- | samples/bpf/trace_event_kern.c | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/samples/bpf/trace_event_kern.c b/samples/bpf/trace_event_kern.c new file mode 100644 index 000000000000..71a8ed32823e --- /dev/null +++ b/samples/bpf/trace_event_kern.c @@ -0,0 +1,65 @@ +/* Copyright (c) 2016 Facebook + * + * 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 <linux/ptrace.h> +#include <linux/version.h> +#include <uapi/linux/bpf.h> +#include <uapi/linux/bpf_perf_event.h> +#include <uapi/linux/perf_event.h> +#include "bpf_helpers.h" + +struct key_t { + char comm[TASK_COMM_LEN]; + u32 kernstack; + u32 userstack; +}; + +struct bpf_map_def SEC("maps") counts = { + .type = BPF_MAP_TYPE_HASH, + .key_size = sizeof(struct key_t), + .value_size = sizeof(u64), + .max_entries = 10000, +}; + +struct bpf_map_def SEC("maps") stackmap = { + .type = BPF_MAP_TYPE_STACK_TRACE, + .key_size = sizeof(u32), + .value_size = PERF_MAX_STACK_DEPTH * sizeof(u64), + .max_entries = 10000, +}; + +#define KERN_STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP) +#define USER_STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP | BPF_F_USER_STACK) + +SEC("perf_event") +int bpf_prog1(struct bpf_perf_event_data *ctx) +{ + char fmt[] = "CPU-%d period %lld ip %llx"; + u32 cpu = bpf_get_smp_processor_id(); + struct key_t key; + u64 *val, one = 1; + + if (ctx->sample_period < 10000) + /* ignore warmup */ + return 0; + bpf_get_current_comm(&key.comm, sizeof(key.comm)); + key.kernstack = bpf_get_stackid(ctx, &stackmap, KERN_STACKID_FLAGS); + key.userstack = bpf_get_stackid(ctx, &stackmap, USER_STACKID_FLAGS); + if ((int)key.kernstack < 0 && (int)key.userstack < 0) { + bpf_trace_printk(fmt, sizeof(fmt), cpu, ctx->sample_period, + ctx->regs.ip); + return 0; + } + + val = bpf_map_lookup_elem(&counts, &key); + if (val) + (*val)++; + else + bpf_map_update_elem(&counts, &key, &one, BPF_NOEXIST); + return 0; +} + +char _license[] SEC("license") = "GPL"; |