From patchwork Mon Sep 12 19:58:47 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Colton Lewis X-Patchwork-Id: 12974085 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 38A27C6FA83 for ; Mon, 12 Sep 2022 19:58:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229739AbiILT6z (ORCPT ); Mon, 12 Sep 2022 15:58:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53012 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229598AbiILT6x (ORCPT ); Mon, 12 Sep 2022 15:58:53 -0400 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C6E2E23BEF for ; Mon, 12 Sep 2022 12:58:52 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-33d9f6f4656so84075617b3.21 for ; Mon, 12 Sep 2022 12:58:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date; bh=rlbt5+zNSyDwJNoOthwq8HRUdQMHAZ0EW6FGx99U/n8=; b=Bz7OB3YFKTZgQWPWmYANlkutLNExXD3tybAbDokzeDiYcaOY9ex2pvTy0V5juWbsan J3fxUrYNxB/m/Q/0/5YQfaaE0LDum8BjTN8fC7fbDit/IE9F9/N1NKjHmNFPMD6GZ+Fi rwEuRPJ6I88axKjuGoWbvx406XU77HBFbWpdvLs7mzvBgBdWM4dl74mdiQn4HUDIxcQi BfRVmS1WDb5SQosrW3939GkQ8embA8PCe8CNQXjgQ2zFDkYsSE7FfW/7W6sorIdoVgzF /oX244XKAVc0UmYZS16JWwoK9qgL9fen34WW95JMLXn/Q2TsnpEKOU9wk+S2Y6S0cdY3 5Nzg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date; bh=rlbt5+zNSyDwJNoOthwq8HRUdQMHAZ0EW6FGx99U/n8=; b=DLI8XIbkHdfx9qPPpWnU4AXF0XETjANr7iOBPAeAggpvH7wXl4670tNODZKzW1onj4 kEnRBq2UTPH5Oeg3z0n3wp17MI0/5DBu5I43NOUYFrkQRjFKsznfmBqWEYismKUpzwvg nTFJ4+626Yn8D50vJp3qhoTuXInvCY4QVTuk/z+ibouS1BoaCdagKprwMNlmNyjgaBqn FfTkQCjYnpW23nj5Ll4wwoKvH1ANq5P7YZbqh23gpqm9LiDG3gVYakgAVTusssdk9trd /seN7LIBZm9a5OZt5tA4Kd8wkV7E9zMyc+0dCS62GlvGqEGj+qGYJ3vR0vLI+cilvCkw Xnuw== X-Gm-Message-State: ACgBeo21lMGYR46TDGRd+sznN9BId7Z35NTJSLuzE1LyjV87PTPybuQ4 yDccHy8rrAPGt26GOcyYBsJsaB0ExYUGdj1B61EAK5BNHZuDM8JMRSUxJNpQoEBDRJ9r3rBhDZ/ vCdujZtRvBOORdqhUTZeu2yl1ols+xn4E68VX5xiV0gfzwfkZGnx9FIIpmCpQoGFBzaLXjTU= X-Google-Smtp-Source: AA6agR5b2wCh93SCXUI8WLqKnRMP5PLDRaQSL72B4J1WB8fDukA8iR34nhskqhJmSpjZkPJeaXy35+5M1B6psYZbKA== X-Received: from coltonlewis-kvm.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:14ce]) (user=coltonlewis job=sendgmr) by 2002:a0d:de83:0:b0:337:c0bf:12ee with SMTP id h125-20020a0dde83000000b00337c0bf12eemr22507349ywe.289.1663012731964; Mon, 12 Sep 2022 12:58:51 -0700 (PDT) Date: Mon, 12 Sep 2022 19:58:47 +0000 In-Reply-To: <20220912195849.3989707-1-coltonlewis@google.com> Mime-Version: 1.0 References: <20220912195849.3989707-1-coltonlewis@google.com> X-Mailer: git-send-email 2.37.2.789.g6183377224-goog Message-ID: <20220912195849.3989707-2-coltonlewis@google.com> Subject: [PATCH v6 1/3] KVM: selftests: implement random number generation for guest code From: Colton Lewis To: kvm@vger.kernel.org Cc: pbonzini@redhat.com, maz@kernel.org, dmatlack@google.com, seanjc@google.com, oupton@google.com, ricarkol@google.com, andrew.jones@linux.dev, Colton Lewis Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Implement random number generation for guest code to randomize parts of the test, making it less predictable and a more accurate reflection of reality. Create a -r argument to specify a random seed. If no argument is provided, the seed defaults to 0. The random seed is set with perf_test_set_random_seed() and must be set before guest_code runs to apply. The random number generator chosen is the Park-Miller Linear Congruential Generator, a fancy name for a basic and well-understood random number generator entirely sufficient for this purpose. Each vCPU calculates its own seed by adding its index to the seed provided. Signed-off-by: Colton Lewis Reviewed-by: Ricardo Koller --- tools/testing/selftests/kvm/dirty_log_perf_test.c | 12 ++++++++++-- tools/testing/selftests/kvm/include/perf_test_util.h | 2 ++ tools/testing/selftests/kvm/include/test_util.h | 2 ++ tools/testing/selftests/kvm/lib/perf_test_util.c | 8 ++++++++ tools/testing/selftests/kvm/lib/test_util.c | 9 +++++++++ 5 files changed, 31 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/kvm/dirty_log_perf_test.c b/tools/testing/selftests/kvm/dirty_log_perf_test.c index d60a34cdfaee..a89a620f50d4 100644 --- a/tools/testing/selftests/kvm/dirty_log_perf_test.c +++ b/tools/testing/selftests/kvm/dirty_log_perf_test.c @@ -126,6 +126,7 @@ struct test_params { bool partition_vcpu_memory_access; enum vm_mem_backing_src_type backing_src; int slots; + uint32_t random_seed; }; static void toggle_dirty_logging(struct kvm_vm *vm, int slots, bool enable) @@ -220,6 +221,9 @@ static void run_test(enum vm_guest_mode mode, void *arg) p->slots, p->backing_src, p->partition_vcpu_memory_access); + /* If no argument provided, random seed will be 0. */ + pr_info("Random seed: %u\n", p->random_seed); + perf_test_set_random_seed(vm, p->random_seed); perf_test_set_wr_fract(vm, p->wr_fract); guest_num_pages = (nr_vcpus * guest_percpu_mem_size) >> vm_get_page_shift(vm); @@ -337,7 +341,7 @@ static void help(char *name) { puts(""); printf("usage: %s [-h] [-i iterations] [-p offset] [-g] " - "[-m mode] [-n] [-b vcpu bytes] [-v vcpus] [-o] [-s mem type]" + "[-m mode] [-n] [-b vcpu bytes] [-v vcpus] [-o] [-r random seed ] [-s mem type]" "[-x memslots]\n", name); puts(""); printf(" -i: specify iteration counts (default: %"PRIu64")\n", @@ -362,6 +366,7 @@ static void help(char *name) printf(" -v: specify the number of vCPUs to run.\n"); printf(" -o: Overlap guest memory accesses instead of partitioning\n" " them into a separate region of memory for each vCPU.\n"); + printf(" -r: specify the starting random seed.\n"); backing_src_help("-s"); printf(" -x: Split the memory region into this number of memslots.\n" " (default: 1)\n"); @@ -388,7 +393,7 @@ int main(int argc, char *argv[]) guest_modes_append_default(); - while ((opt = getopt(argc, argv, "ghi:p:m:nb:f:v:os:x:")) != -1) { + while ((opt = getopt(argc, argv, "ghi:p:m:nb:f:v:or:s:x:")) != -1) { switch (opt) { case 'g': dirty_log_manual_caps = 0; @@ -421,6 +426,9 @@ int main(int argc, char *argv[]) case 'o': p.partition_vcpu_memory_access = false; break; + case 'r': + p.random_seed = atoi(optarg); + break; case 's': p.backing_src = parse_backing_src_type(optarg); break; diff --git a/tools/testing/selftests/kvm/include/perf_test_util.h b/tools/testing/selftests/kvm/include/perf_test_util.h index d822cb670f1c..f18530984b42 100644 --- a/tools/testing/selftests/kvm/include/perf_test_util.h +++ b/tools/testing/selftests/kvm/include/perf_test_util.h @@ -34,6 +34,7 @@ struct perf_test_args { uint64_t gpa; uint64_t size; uint64_t guest_page_size; + uint32_t random_seed; int wr_fract; /* Run vCPUs in L2 instead of L1, if the architecture supports it. */ @@ -51,6 +52,7 @@ struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int vcpus, void perf_test_destroy_vm(struct kvm_vm *vm); void perf_test_set_wr_fract(struct kvm_vm *vm, int wr_fract); +void perf_test_set_random_seed(struct kvm_vm *vm, uint32_t random_seed); void perf_test_start_vcpu_threads(int vcpus, void (*vcpu_fn)(struct perf_test_vcpu_args *)); void perf_test_join_vcpu_threads(int vcpus); diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h index 99e0dcdc923f..2dd286bcf46f 100644 --- a/tools/testing/selftests/kvm/include/test_util.h +++ b/tools/testing/selftests/kvm/include/test_util.h @@ -143,4 +143,6 @@ static inline void *align_ptr_up(void *x, size_t size) return (void *)align_up((unsigned long)x, size); } +void guest_random(uint32_t *seed); + #endif /* SELFTEST_KVM_TEST_UTIL_H */ diff --git a/tools/testing/selftests/kvm/lib/perf_test_util.c b/tools/testing/selftests/kvm/lib/perf_test_util.c index f989ff91f022..b1e731de0966 100644 --- a/tools/testing/selftests/kvm/lib/perf_test_util.c +++ b/tools/testing/selftests/kvm/lib/perf_test_util.c @@ -47,6 +47,7 @@ void perf_test_guest_code(uint32_t vcpu_id) uint64_t gva; uint64_t pages; int i; + uint32_t rand = pta->random_seed + vcpu_id; /* Make sure vCPU args data structure is not corrupt. */ GUEST_ASSERT(vcpu_args->vcpu_id == vcpu_id); @@ -57,6 +58,7 @@ void perf_test_guest_code(uint32_t vcpu_id) while (true) { for (i = 0; i < pages; i++) { uint64_t addr = gva + (i * pta->guest_page_size); + guest_random(&rand); if (i % pta->wr_fract == 0) *(uint64_t *)addr = 0x0123456789ABCDEF; @@ -224,6 +226,12 @@ void perf_test_set_wr_fract(struct kvm_vm *vm, int wr_fract) sync_global_to_guest(vm, perf_test_args); } +void perf_test_set_random_seed(struct kvm_vm *vm, uint32_t random_seed) +{ + perf_test_args.random_seed = random_seed; + sync_global_to_guest(vm, perf_test_args.random_seed); +} + uint64_t __weak perf_test_nested_pages(int nr_vcpus) { return 0; diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c index 6d23878bbfe1..28c895743abe 100644 --- a/tools/testing/selftests/kvm/lib/test_util.c +++ b/tools/testing/selftests/kvm/lib/test_util.c @@ -17,6 +17,15 @@ #include "test_util.h" +/* + * Random number generator that is usable from guest code. This is the + * Park-Miller LCG using standard constants. + */ +void guest_random(uint32_t *seed) +{ + *seed = (uint64_t)*seed * 48271 % ((uint32_t)(1 << 31) - 1); +} + /* * Parses "[0-9]+[kmgt]?". */