From patchwork Thu Sep 8 20:53:45 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Colton Lewis X-Patchwork-Id: 12970653 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 93510C38145 for ; Thu, 8 Sep 2022 20:54:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229849AbiIHUyu (ORCPT ); Thu, 8 Sep 2022 16:54:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52672 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229670AbiIHUyo (ORCPT ); Thu, 8 Sep 2022 16:54:44 -0400 Received: from mail-io1-xd49.google.com (mail-io1-xd49.google.com [IPv6:2607:f8b0:4864:20::d49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4D9842AE31 for ; Thu, 8 Sep 2022 13:54:43 -0700 (PDT) Received: by mail-io1-xd49.google.com with SMTP id e4-20020a5d85c4000000b0068bb3c11e72so12104798ios.5 for ; Thu, 08 Sep 2022 13:54:43 -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=+cGIHyyO/TObOL7RYYQROdZlDl2AFQdBqWIubWPNzGw=; b=m9A+XnVLARCaWaq0pITM2D6L68ChVdF1/5X+2IFDCjPrfSEUELq+DVHh3FlXKADq2B bWxi7qg2iPQ6yUh4vZnCGXpEZTZJ4P9PllpME5SIUNUWsALHdwOsqaFmeolTRWExqT5Y tS+OwQ/em//WkJu2an9Yvke5DwTzHJPq0SAfWjnU/1FfYhRcgdEeNQo1OgY/HZseKGCN MZxKiWdoDkmV8IlKWKavR4Xd6QtYnFM4ywXrOoCn81rEqW/dE9LqVpGWovnT7WO+2Hy0 ys0uf3qfrMfnRmL0QIEDKb2blseKklAYREalMRiCzDxWMR3GmC4d2v1E3qcXN9ctGfql xuuw== 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=+cGIHyyO/TObOL7RYYQROdZlDl2AFQdBqWIubWPNzGw=; b=PCNjQg7zA/NhnBRsM7s+9Th1lUMluHkTDPdNcr3k8ENOKNRrn3jvnQ8rs+eQjNm/Zg lVg0ELk+QXk4Ar6hxrqGq/QYbcIjRciIQ52DEbFwhSNCJtr9qtEmTuuZBg7S99jyzb8q XLBXThUzYy741vNzi56KJKn3NC4SCAfrHG1/DUMpUYBpucYoMgTehD3JTexlof93LZF2 LUPf8LmNbVGnm+a2ESbN+opUJ6VMgGLThYD7BxhPOmKsZqF94baQTZX9bbzVFxH0fPKm mfoS/A5lsY0ra1FjijFlIynCriskdgfKuGi1NOXOWQKPyftd7Y5V31wczjxceXQhlr17 SdRA== X-Gm-Message-State: ACgBeo27V9o0j9wPHK5b83rKsBYjbu3oJolpxUbByrDWviMI2jlC690G Mcv5CSTJF44+rAWWJGmyqgwR3ice2E4BIG+9WdtLufCplk16oIdnOOHotspXvhKQRTL8pl+wr08 iw1ePbVFjurEYB1cB5tBWXEQRyJOeeyl/HKUezvZ6//Tr+ALMYFhIYkzEIYULtdl7N59kgMM= X-Google-Smtp-Source: AA6agR6Iyt7+iEUSCbUbULsj6MJH4bOPvOiO9gDr30LsKLKwVCFm+338Q5LkpqAa3/gX6wCesRnm1XdK0zAqL/rxXA== X-Received: from coltonlewis-kvm.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:14ce]) (user=coltonlewis job=sendgmr) by 2002:a92:cdae:0:b0:2f1:8d4e:403e with SMTP id g14-20020a92cdae000000b002f18d4e403emr2777227ild.129.1662670482599; Thu, 08 Sep 2022 13:54:42 -0700 (PDT) Date: Thu, 8 Sep 2022 20:53:45 +0000 In-Reply-To: <20220908205347.3284344-1-coltonlewis@google.com> Mime-Version: 1.0 References: <20220908205347.3284344-1-coltonlewis@google.com> X-Mailer: git-send-email 2.37.2.789.g6183377224-goog Message-ID: <20220908205347.3284344-2-coltonlewis@google.com> Subject: [PATCH v4 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 the current Unix timestamp. 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 --- 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 | 11 ++++++++++- tools/testing/selftests/kvm/lib/test_util.c | 9 +++++++++ 5 files changed, 33 insertions(+), 3 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..2f91acd94130 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 +221,8 @@ static void run_test(enum vm_guest_mode mode, void *arg) p->slots, p->backing_src, p->partition_vcpu_memory_access); + 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 +340,7 @@ 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 +365,7 @@ 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"); @@ -378,6 +382,7 @@ int main(int argc, char *argv[]) .partition_vcpu_memory_access = true, .backing_src = DEFAULT_VM_MEM_SRC, .slots = 1, + .random_seed = time(NULL), }; int opt; @@ -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..4d9c7d7693d9 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; @@ -115,8 +117,9 @@ struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int vcpus, pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode)); - /* By default vCPUs will write to memory. */ + /* Set perf_test_args defaults. */ pta->wr_fract = 1; + pta->random_seed = time(NULL); /* * Snapshot the non-huge page size. This is used by the guest code to @@ -224,6 +227,12 @@ 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]?". */