From patchwork Wed Oct 19 22:13:20 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Colton Lewis X-Patchwork-Id: 13012380 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 64B6FC433FE for ; Wed, 19 Oct 2022 22:13:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231390AbiJSWNx (ORCPT ); Wed, 19 Oct 2022 18:13:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40896 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230452AbiJSWNw (ORCPT ); Wed, 19 Oct 2022 18:13:52 -0400 Received: from mail-io1-xd4a.google.com (mail-io1-xd4a.google.com [IPv6:2607:f8b0:4864:20::d4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5C9D3180248 for ; Wed, 19 Oct 2022 15:13:51 -0700 (PDT) Received: by mail-io1-xd4a.google.com with SMTP id i21-20020a6bf415000000b006bc987bf9faso14520201iog.6 for ; Wed, 19 Oct 2022 15:13:51 -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:message-id:reply-to; bh=d34GJO7GQ09PGPUyUIG1XPP0AAT2WAOYMqmwwCDblFA=; b=bOwATuv54F32dJOh1J1dvgbZ1plvIWx6Xsp4Yz30MLMFn3UNM7IyTGNxvL6etio4c1 EQjaW3+p16ieNejng1iIIYCDHG9LyeVIeiuR2X/Owe66yxiBfDePPFisWMsV/tkiN/GJ sIIA6zfCdthcqsdFAU5PfJa7IpJRSpN/owQvKPhUb37Wq9bGFw9HhpwSZEZGX+O+kJHL 4Zg1r7kZMyM58dwLFYrzu7FIrsCSNzY9ELGWnvjwCDnqVk96Bsu9vHb1yO1ieV56LV3l OwEHJI0113k+BY9A8RcnVjHrenAS/rhpdigEqWRGWJvdI+M5n+jPMzXKasW2m4S4HiOQ V+Pw== 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:message-id:reply-to; bh=d34GJO7GQ09PGPUyUIG1XPP0AAT2WAOYMqmwwCDblFA=; b=dB4Mq0l1hV41HD+qw+2qFmwPuruaDCFjWC6Eq/9m6OMX+BXy/cIuJM3N4QziDUn2fK vv+4+gQKouakmPSMiJhZCU76l1LgoSQYpJ0eS+uZy2EVEpkfrALcV6paF0MH5jfE2K8B maJwNwfngDJJNKY0cXyQEc/uikKWH40JmIThFhV8jYc1OimHGqwrnwYFz7M9bG0YKTcv GZ84Vv0iPoObJn9lS2mhksIOi/NRwXVB/tg2k6czVtwovrQuAeYtY/DhLAn9aNTmSTyf 8R5rIomoxnadcnl/AJY7QXRhNckVI/1rGoUtBgfOB7b9PF8dQ+dP0hiuWpbJjseHZvO8 i8uw== X-Gm-Message-State: ACrzQf37ak6cUKXlCf0fP5dpDJ2NveYxBxMgainzXVk9AcTO/yVGq7jI RqotXh4gopBlsURJ4YMHMP9gSRKG4+PCjQr25cePvFjIbbClINIye3yzmpgsVIakkZOHp8fCgiu Jn4cIKDPCDiQ97eGhG+mulyAL7SV9sR24FTSpjVCoA2uMhquNZZDiSin0Uh5SzM0ezBdbKms= X-Google-Smtp-Source: AMsMyM5w/coArMyUVLqD1Jx9/k9Wn6kQ7Lx5BvQwQXheRurjtWz+yyEUIrHdHYHbLKgLSMYlM7NhRfT6F6dep0FeNg== X-Received: from coltonlewis-kvm.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:14ce]) (user=coltonlewis job=sendgmr) by 2002:a5d:9859:0:b0:6bb:4dff:8a8b with SMTP id p25-20020a5d9859000000b006bb4dff8a8bmr6992039ios.159.1666217630780; Wed, 19 Oct 2022 15:13:50 -0700 (PDT) Date: Wed, 19 Oct 2022 22:13:20 +0000 In-Reply-To: <20221019221321.3033920-1-coltonlewis@google.com> Mime-Version: 1.0 References: <20221019221321.3033920-1-coltonlewis@google.com> X-Mailer: git-send-email 2.38.0.413.g74048e4d9e-goog Message-ID: <20221019221321.3033920-3-coltonlewis@google.com> Subject: [PATCH v7 2/3] KVM: selftests: randomize which pages are written vs read 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, Colton Lewis Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Randomize which pages are written vs read using the random number generator. Change the variable wr_fract and associated function calls to write_percent that now operates as a percentage from 0 to 100 where X means each page has an X% chance of being written. Change the -f argument to -w to reflect the new variable semantics. Keep the same default of 100% writes. Population always uses 100% writes to ensure all memory is actually populated and not just mapped to the zero page. The prevents expensive copy-on-write faults from occurring during the dirty memory iterations below, which would pollute the performance results. Signed-off-by: Colton Lewis Reviewed-by: Ricardo Koller Reviewed-by: David Matlack --- .../selftests/kvm/access_tracking_perf_test.c | 2 +- .../selftests/kvm/dirty_log_perf_test.c | 38 ++++++++++++------- .../selftests/kvm/include/perf_test_util.h | 4 +- .../selftests/kvm/lib/perf_test_util.c | 10 ++--- 4 files changed, 33 insertions(+), 21 deletions(-) diff --git a/tools/testing/selftests/kvm/access_tracking_perf_test.c b/tools/testing/selftests/kvm/access_tracking_perf_test.c index 76c583a07ea2..3e16d5bd7856 100644 --- a/tools/testing/selftests/kvm/access_tracking_perf_test.c +++ b/tools/testing/selftests/kvm/access_tracking_perf_test.c @@ -279,7 +279,7 @@ static void run_iteration(struct kvm_vm *vm, int nr_vcpus, const char *descripti static void access_memory(struct kvm_vm *vm, int nr_vcpus, enum access_type access, const char *description) { - perf_test_set_wr_fract(vm, (access == ACCESS_READ) ? INT_MAX : 1); + perf_test_set_write_percent(vm, (access == ACCESS_READ) ? 0 : 100); iteration_work = ITERATION_ACCESS_MEMORY; run_iteration(vm, nr_vcpus, description); } diff --git a/tools/testing/selftests/kvm/dirty_log_perf_test.c b/tools/testing/selftests/kvm/dirty_log_perf_test.c index c97a5e455699..0d0240041acf 100644 --- a/tools/testing/selftests/kvm/dirty_log_perf_test.c +++ b/tools/testing/selftests/kvm/dirty_log_perf_test.c @@ -128,10 +128,10 @@ static void vcpu_worker(struct perf_test_vcpu_args *vcpu_args) struct test_params { unsigned long iterations; uint64_t phys_offset; - int wr_fract; bool partition_vcpu_memory_access; enum vm_mem_backing_src_type backing_src; int slots; + uint32_t write_percent; uint32_t random_seed; }; @@ -229,7 +229,7 @@ static void run_test(enum vm_guest_mode mode, void *arg) /* If no argument provided, random seed will be 1. */ pr_info("Random seed: %u\n", p->random_seed); perf_test_set_random_seed(vm, p->random_seed ? p->random_seed : 1); - perf_test_set_wr_fract(vm, p->wr_fract); + perf_test_set_write_percent(vm, p->write_percent); guest_num_pages = (nr_vcpus * guest_percpu_mem_size) >> vm->page_shift; guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages); @@ -252,6 +252,14 @@ static void run_test(enum vm_guest_mode mode, void *arg) for (i = 0; i < nr_vcpus; i++) vcpu_last_completed_iteration[i] = -1; + /* + * Use 100% writes during the population phase to ensure all + * memory is actually populated and not just mapped to the zero + * page. The prevents expensive copy-on-write faults from + * occurring during the dirty memory iterations below, which + * would pollute the performance results. + */ + perf_test_set_write_percent(vm, 100); perf_test_start_vcpu_threads(nr_vcpus, vcpu_worker); /* Allow the vCPUs to populate memory */ @@ -273,6 +281,8 @@ static void run_test(enum vm_guest_mode mode, void *arg) pr_info("Enabling dirty logging time: %ld.%.9lds\n\n", ts_diff.tv_sec, ts_diff.tv_nsec); + perf_test_set_write_percent(vm, p->write_percent); + while (iteration < p->iterations) { /* * Incrementing the iteration number will start the vCPUs @@ -357,7 +367,7 @@ static void help(char *name) puts(""); printf("usage: %s [-h] [-i iterations] [-p offset] [-g] " "[-m mode] [-n] [-b vcpu bytes] [-v vcpus] [-o] [-r random seed ] [-s mem type]" - "[-x memslots]\n", name); + "[-x memslots] [-w percentage]\n", name); puts(""); printf(" -i: specify iteration counts (default: %"PRIu64")\n", TEST_HOST_LOOP_N); @@ -377,10 +387,6 @@ static void help(char *name) printf(" -b: specify the size of the memory region which should be\n" " dirtied by each vCPU. e.g. 10M or 3G.\n" " (default: 1G)\n"); - printf(" -f: specify the fraction of pages which should be written to\n" - " as opposed to simply read, in the form\n" - " 1/.\n" - " (default: 1 i.e. all pages are written to.)\n"); 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"); @@ -388,6 +394,11 @@ static void help(char *name) backing_src_help("-s"); printf(" -x: Split the memory region into this number of memslots.\n" " (default: 1)\n"); + printf(" -w: specify the percentage of pages which should be written to\n" + " as an integer from 0-100 inclusive. This is probabalistic,\n" + " so -w X means each page has an X%% chance of writing\n" + " and a (100-X)%% chance of reading.\n" + " (default: 100 i.e. all pages are written to.)\n"); puts(""); exit(0); } @@ -397,10 +408,10 @@ int main(int argc, char *argv[]) int max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS); struct test_params p = { .iterations = TEST_HOST_LOOP_N, - .wr_fract = 1, .partition_vcpu_memory_access = true, .backing_src = DEFAULT_VM_MEM_SRC, .slots = 1, + .write_percent = 100, }; int opt; @@ -411,7 +422,7 @@ int main(int argc, char *argv[]) guest_modes_append_default(); - while ((opt = getopt(argc, argv, "eghi:p:m:nb:f:v:or:s:x:")) != -1) { + while ((opt = getopt(argc, argv, "eghi:p:m:nb:v:or:s:x:w:")) != -1) { switch (opt) { case 'e': /* 'e' is for evil. */ @@ -434,10 +445,11 @@ int main(int argc, char *argv[]) case 'b': guest_percpu_mem_size = parse_size(optarg); break; - case 'f': - p.wr_fract = atoi(optarg); - TEST_ASSERT(p.wr_fract >= 1, - "Write fraction cannot be less than one"); + case 'w': + p.write_percent = atoi(optarg); + TEST_ASSERT(p.write_percent >= 0 + && p.write_percent <= 100, + "Write percentage must be between 0 and 100"); break; case 'v': nr_vcpus = atoi(optarg); diff --git a/tools/testing/selftests/kvm/include/perf_test_util.h b/tools/testing/selftests/kvm/include/perf_test_util.h index f1050fd42d10..845165001ec8 100644 --- a/tools/testing/selftests/kvm/include/perf_test_util.h +++ b/tools/testing/selftests/kvm/include/perf_test_util.h @@ -36,7 +36,7 @@ struct perf_test_args { uint64_t size; uint64_t guest_page_size; uint32_t random_seed; - int wr_fract; + uint32_t write_percent; /* Run vCPUs in L2 instead of L1, if the architecture supports it. */ bool nested; @@ -52,7 +52,7 @@ struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int nr_vcpus, bool partition_vcpu_memory_access); 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_write_percent(struct kvm_vm *vm, uint32_t write_percent); 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 *)); diff --git a/tools/testing/selftests/kvm/lib/perf_test_util.c b/tools/testing/selftests/kvm/lib/perf_test_util.c index 5f0eebb626b5..97a402f5ed23 100644 --- a/tools/testing/selftests/kvm/lib/perf_test_util.c +++ b/tools/testing/selftests/kvm/lib/perf_test_util.c @@ -61,7 +61,7 @@ void perf_test_guest_code(uint32_t vcpu_idx) for (i = 0; i < pages; i++) { uint64_t addr = gva + (i * pta->guest_page_size); - if (i % pta->wr_fract == 0) + if (guest_random_u32(&rand_state) % 100 < pta->write_percent) *(uint64_t *)addr = 0x0123456789ABCDEF; else READ_ONCE(*(uint64_t *)addr); @@ -122,7 +122,7 @@ struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int nr_vcpus, pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode)); /* By default vCPUs will write to memory. */ - pta->wr_fract = 1; + pta->write_percent = 100; /* * Snapshot the non-huge page size. This is used by the guest code to @@ -224,10 +224,10 @@ void perf_test_destroy_vm(struct kvm_vm *vm) kvm_vm_free(vm); } -void perf_test_set_wr_fract(struct kvm_vm *vm, int wr_fract) +void perf_test_set_write_percent(struct kvm_vm *vm, uint32_t write_percent) { - perf_test_args.wr_fract = wr_fract; - sync_global_to_guest(vm, perf_test_args); + perf_test_args.write_percent = write_percent; + sync_global_to_guest(vm, perf_test_args.write_percent); } void perf_test_set_random_seed(struct kvm_vm *vm, uint32_t random_seed)