int do_perf_event()

in profiler/profile.bpf.c [163:214]

• 41 lines of code
• 15 McCabe index (conditional complexity)

int do_perf_event(struct bpf_perf_event_data *ctx)
{
	__u64 id = bpf_get_current_pid_tgid();
	__u32 pid = id >> 32;
	__u32 tid = id;
	__u64 *valp;
	static const __u64 zero;
	struct stack_key key = {};

	if (!include_idle && tid == 0)
		return 0;

	if (targ_pid != -1 && targ_pid != pid)
		return 0;
	if (targ_tid != -1 && targ_tid != tid)
		return 0;

	key.pid = pid;
	bpf_get_current_comm(&key.name, sizeof(key.name));

	if (user_stacks_only)
		key.kern_stack_id = -1;
	else
		key.kern_stack_id = bpf_get_stackid(&ctx->regs, &stackmap, 0);

	if (kernel_stacks_only)
		key.user_stack_id = -1;
	else
		key.user_stack_id = bpf_get_stackid(&ctx->regs, &stackmap, BPF_F_USER_STACK);

	if (key.kern_stack_id >= 0)
	{
		// populate extras to fix the kernel stack
		__u64 ip = PT_REGS_IP(&ctx->regs);

		if (is_kernel_addr(ip))
		{
			key.kernel_ip = ip;
		}
	}

	valp = bpf_map_lookup_or_try_init(&counts, &key, &zero);
	if (valp)
		__sync_fetch_and_add(valp, 1);

	if (!disable_lua_user_trace && (!valp || *valp <= 1))
	{
		// only get lua stack the first time we found a new stack id
		fix_lua_stack(ctx, tid, key.user_stack_id);
	}
	return 0;
}