selftests/bpf: add realistic loop tests

Add a bunch of loop tests. Most of them are created by replacing
'#pragma unroll' with '#pragma clang loop unroll(disable)'

Several tests are artificially large:
  /* partial unroll. llvm will unroll loop ~150 times.
   * C loop count -> 600.
   * Asm loop count -> 4.
   * 16k insns in loop body.
   * Total of 5 such loops. Total program size ~82k insns.
   */
  "./pyperf600.o",

  /* no unroll at all.
   * C loop count -> 600.
   * ASM loop count -> 600.
   * ~110 insns in loop body.
   * Total of 5 such loops. Total program size ~1500 insns.
   */
  "./pyperf600_nounroll.o",

  /* partial unroll. 19k insn in a loop.
   * Total program size 20.8k insn.
   * ~350k processed_insns
   */
  "./strobemeta.o",

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

1 files changed, 28 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/progs/loop2.c b/tools/testing/selftests/bpf/progs/loop2.c
new file mode 100644
index 000000000000..0637bd8e8bcf
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/loop2.c
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Facebook
+#include <linux/sched.h>
+#include <linux/ptrace.h>
+#include <stdint.h>
+#include <stddef.h>
+#include <stdbool.h>
+#include <linux/bpf.h>
+#include "bpf_helpers.h"
+
+char _license[] SEC("license") = "GPL";
+
+SEC("raw_tracepoint/consume_skb")
+int while_true(volatile struct pt_regs* ctx)
+{
+	int i = 0;
+
+	while (true) {
+		if (ctx->rax & 1)
+			i += 3;
+		else
+			i += 7;
+		if (i > 40)
+			break;
+	}
+
+	return i;
+}