[RFC bpf-next 11/11] selftests/bpf: dynptr_slice benchmark

[Eduard Zingerman <eddyz87@gmail.com>]

Benchmark to measure execution time of a simple bpf_dynptr_slice()
call, when dynptr type is known and buffer__opt parameter is null.
Under such conditions verifier inline the kfunc call and delete a
couple of conditionals in the body of the kfunc.

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
---
 tools/testing/selftests/bpf/Makefile          |  2 +
 tools/testing/selftests/bpf/bench.c           |  2 +
 .../selftests/bpf/benchs/bench_dynptr_slice.c | 76 +++++++++++++++++++
 .../selftests/bpf/progs/dynptr_slice_bench.c  | 29 +++++++
 4 files changed, 109 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/benchs/bench_dynptr_slice.c
 create mode 100644 tools/testing/selftests/bpf/progs/dynptr_slice_bench.c

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index edef5df08cb2..3a938d5b295f 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -845,6 +845,7 @@ $(OUTPUT)/bench_local_storage_create.o: $(OUTPUT)/bench_local_storage_create.ske
 $(OUTPUT)/bench_bpf_hashmap_lookup.o: $(OUTPUT)/bpf_hashmap_lookup.skel.h
 $(OUTPUT)/bench_htab_mem.o: $(OUTPUT)/htab_mem_bench.skel.h
 $(OUTPUT)/bench_bpf_crypto.o: $(OUTPUT)/crypto_bench.skel.h
+$(OUTPUT)/bench_dynptr_slice.o: $(OUTPUT)/dynptr_slice_bench.skel.h
 $(OUTPUT)/bench.o: bench.h testing_helpers.h $(BPFOBJ)
 $(OUTPUT)/bench: LDLIBS += -lm
 $(OUTPUT)/bench: $(OUTPUT)/bench.o \
@@ -865,6 +866,7 @@ $(OUTPUT)/bench: $(OUTPUT)/bench.o \
 		 $(OUTPUT)/bench_local_storage_create.o \
 		 $(OUTPUT)/bench_htab_mem.o \
 		 $(OUTPUT)/bench_bpf_crypto.o \
+		 $(OUTPUT)/bench_dynptr_slice.o \
 		 #
 	$(call msg,BINARY,,$@)
 	$(Q)$(CC) $(CFLAGS) $(LDFLAGS) $(filter %.a %.o,$^) $(LDLIBS) -o $@
diff --git a/tools/testing/selftests/bpf/bench.c b/tools/testing/selftests/bpf/bench.c
index 1bd403a5ef7b..74053665465c 100644
--- a/tools/testing/selftests/bpf/bench.c
+++ b/tools/testing/selftests/bpf/bench.c
@@ -549,6 +549,7 @@ extern const struct bench bench_local_storage_create;
 extern const struct bench bench_htab_mem;
 extern const struct bench bench_crypto_encrypt;
 extern const struct bench bench_crypto_decrypt;
+extern const struct bench bench_dynptr_slice;
 
 static const struct bench *benchs[] = {
 	&bench_count_global,
@@ -609,6 +610,7 @@ static const struct bench *benchs[] = {
 	&bench_htab_mem,
 	&bench_crypto_encrypt,
 	&bench_crypto_decrypt,
+	&bench_dynptr_slice,
 };
 
 static void find_benchmark(void)
diff --git a/tools/testing/selftests/bpf/benchs/bench_dynptr_slice.c b/tools/testing/selftests/bpf/benchs/bench_dynptr_slice.c
new file mode 100644
index 000000000000..957ecc6f1531
--- /dev/null
+++ b/tools/testing/selftests/bpf/benchs/bench_dynptr_slice.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
+
+#include <argp.h>
+#include "bench.h"
+#include "dynptr_slice_bench.skel.h"
+
+static struct dynptr_slice_ctx {
+	struct dynptr_slice_bench *skel;
+	int pfd;
+} ctx;
+
+static void dynptr_slice_validate(void)
+{
+	if (env.consumer_cnt != 0) {
+		fprintf(stderr, "bpf dynptr_slice benchmark doesn't support consumer!\n");
+		exit(1);
+	}
+}
+
+static void dynptr_slice_setup(void)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, opts);
+	int err;
+
+	setup_libbpf();
+	ctx.skel = dynptr_slice_bench__open();
+	if (!ctx.skel) {
+		fprintf(stderr, "failed to open skeleton\n");
+		exit(1);
+	}
+
+	ctx.skel->bss->hits = 0;
+	err = dynptr_slice_bench__load(ctx.skel);
+	if (err) {
+		fprintf(stderr, "failed to load skeleton\n");
+		dynptr_slice_bench__destroy(ctx.skel);
+		exit(1);
+	}
+}
+
+static void dynptr_slice_encrypt_setup(void)
+{
+	dynptr_slice_setup();
+	ctx.pfd = bpf_program__fd(ctx.skel->progs.dynptr_slice);
+}
+
+
+static void dynptr_slice_measure(struct bench_res *res)
+{
+	res->hits = atomic_swap(&ctx.skel->bss->hits, 0);
+}
+
+static void *dynptr_slice_producer(void *unused)
+{
+	static const char data_in[1000];
+	LIBBPF_OPTS(bpf_test_run_opts, opts,
+		.repeat = 64,
+		.data_in = data_in,
+		.data_size_in = sizeof(data_in),
+	);
+
+	while (true)
+		(void)bpf_prog_test_run_opts(ctx.pfd, &opts);
+	return NULL;
+}
+
+const struct bench bench_dynptr_slice = {
+	.name = "dynptr_slice",
+	.validate = dynptr_slice_validate,
+	.setup = dynptr_slice_encrypt_setup,
+	.producer_thread = dynptr_slice_producer,
+	.measure = dynptr_slice_measure,
+	.report_progress = hits_drops_report_progress,
+	.report_final = hits_drops_report_final,
+};
diff --git a/tools/testing/selftests/bpf/progs/dynptr_slice_bench.c b/tools/testing/selftests/bpf/progs/dynptr_slice_bench.c
new file mode 100644
index 000000000000..65a493426b5e
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/dynptr_slice_bench.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include "bpf_compiler.h"
+#include "bpf_kfuncs.h"
+
+long hits = 0;
+
+SEC("tc")
+int dynptr_slice(struct __sk_buff *skb)
+{
+	struct bpf_dynptr psrc;
+	const int N = 100;
+	int i;
+
+	bpf_dynptr_from_skb(skb, 0, &psrc);
+__pragma_loop_unroll_full
+	for (i = 0; i < N; ++i) {
+		bpf_dynptr_slice(&psrc, i, NULL, 1);
+	}
+	__sync_add_and_fetch(&hits, N);
+
+	return 0;
+}
+
+char __license[] SEC("license") = "GPL";
-- 
2.47.0