From patchwork Thu Mar 16 22:27:52 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Colton Lewis X-Patchwork-Id: 13178377 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 A4024C74A5B for ; Thu, 16 Mar 2023 22:30:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229787AbjCPWaL (ORCPT ); Thu, 16 Mar 2023 18:30:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230266AbjCPW36 (ORCPT ); Thu, 16 Mar 2023 18:29:58 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B4070B2547 for ; Thu, 16 Mar 2023 15:29:25 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id e129-20020a251e87000000b00b56598237f5so3285270ybe.16 for ; Thu, 16 Mar 2023 15:29:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; t=1679005760; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=oGx/FV+T8C2lIINfKZXB9UOQoYXHWxwp3UMyuE3rQrU=; b=OezShiy8cUib6NGOk1qMlYfpYZUgzEKJv3qrXwaSa2efJ6OiRyfBrUAc2fibFVWh99 ayaHTboG8pZ+jnL0U3x9+RXcrdjGbEMa+TgQ4j9xZm+7cTy0rTOr4kV5JCqDIk81p5K9 M9amlDm8cg66JoBgwxM5sx4dU/jxk/HbWS1EQeIdukzieLE+tQ341OBCPLUdBgaYrLA1 lKLOPm6K4uH8h0L9vAYV+N9/iPokYn8oqeD2qWOoyFPICLwNt/3ivKPOsPVZ+7DNmEYE 9I6kpoqGPtwjOoBrEZmbUKexVcYOT9mDI7B/Rinaw1ESPuN5zS0tZajcfYGBCtNHW5sE QuMA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679005760; 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=oGx/FV+T8C2lIINfKZXB9UOQoYXHWxwp3UMyuE3rQrU=; b=rz96J2U2/L30JVabZfYhiHsdh9hgSk/kfQUiDZ5CpdzXTFtsnm55sUG0edOV9RVbAn CfLNiG52caFDQI2iVvzIdSWXRqpuuzhDynfTRE8+JiMsTC48on0R2YshX5Bg7Qfdcfj5 Vl7Hb4mG4Nna53LDjjOj9K0B2pTpfMEwwC9pG69IYGDVFY8jMvLAkbJ3yndtAzLhCkIv lpYV3Njg8wy+NpSXLj3GZcBSAj8xytR8z2hRa2dGX9yhP7kPhF13f1w88JRv7iQK8nKW XYHfHc3s3Brl+nTHKde0OuQhxOtolI5Y52p9wiQl+dH6RYF7Laa0OBlgecKojCOlO+BK 3agA== X-Gm-Message-State: AO0yUKX6Td6CX9ybShEm0cdmyiYHbRWa14F77TfUAkLAm4KH+M9P0Rfs 9UFJZOjjHCg3rHoGt7aSS4fu5HC14Z75zMPHLQ== X-Google-Smtp-Source: AK7set8IRAtXk7dkN09rDG5K+EHWhjVlsWkdhSL5UrBGrQlGO0Xo9Jf4wiY3QZWUvTnEQUDPthBoOUT/bhmauBlC7A== X-Received: from coltonlewis-kvm.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:14ce]) (user=coltonlewis job=sendgmr) by 2002:a05:6902:188:b0:a99:de9d:d504 with SMTP id t8-20020a056902018800b00a99de9dd504mr28949992ybh.12.1679005760710; Thu, 16 Mar 2023 15:29:20 -0700 (PDT) Date: Thu, 16 Mar 2023 22:27:52 +0000 In-Reply-To: <20230316222752.1911001-1-coltonlewis@google.com> Mime-Version: 1.0 References: <20230316222752.1911001-1-coltonlewis@google.com> X-Mailer: git-send-email 2.40.0.rc1.284.g88254d51c5-goog Message-ID: <20230316222752.1911001-3-coltonlewis@google.com> Subject: [PATCH v2 2/2] KVM: selftests: Print summary stats of memory latency distribution From: Colton Lewis To: Paolo Bonzini , Shuah Khan , Colton Lewis , Sean Christopherson , David Matlack , Vipin Sharma , Andrew Jones , Marc Zyngier , Ben Gardon , Ricardo Koller , Oliver Upton Cc: kvm@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Print summary stats of the memory latency distribution in nanoseconds for dirty_log_perf_test. For every iteration, this prints the minimum, the maximum, and the 50th, 90th, and 99th percentiles. Stats are calculated by sorting the samples taken from all vcpus and picking from the index corresponding with each percentile. Because keeping all samples is impractical due to the space required in some cases (pooled memory w/ 64 vcpus would be 64 GB/vcpu * 64 vcpus * 250,000 samples/GB * 8 bytes/sample ~ 8 GB extra memory just for samples), reservoir sampling [1] is used to only keep a small number of samples per vcpu (settable via command argument). There is a tradeoff between stat accuracy and memory usage. More samples means more accuracy but also more memory use. Because other selftests use memstress.c, those tests were hardcoded to take 0 samples at this time. [1] https://en.wikipedia.org/wiki/Reservoir_sampling#Simple:_Algorithm_R Signed-off-by: Colton Lewis --- .../selftests/kvm/access_tracking_perf_test.c | 3 +- .../selftests/kvm/demand_paging_test.c | 2 +- .../selftests/kvm/dirty_log_perf_test.c | 10 ++- .../testing/selftests/kvm/include/memstress.h | 10 ++- tools/testing/selftests/kvm/lib/memstress.c | 68 ++++++++++++++++--- .../kvm/memslot_modification_stress_test.c | 2 +- 6 files changed, 81 insertions(+), 14 deletions(-) -- 2.40.0.rc1.284.g88254d51c5-goog diff --git a/tools/testing/selftests/kvm/access_tracking_perf_test.c b/tools/testing/selftests/kvm/access_tracking_perf_test.c index 3c7defd34f56..89947aa4ff3a 100644 --- a/tools/testing/selftests/kvm/access_tracking_perf_test.c +++ b/tools/testing/selftests/kvm/access_tracking_perf_test.c @@ -306,7 +306,8 @@ static void run_test(enum vm_guest_mode mode, void *arg) struct kvm_vm *vm; int nr_vcpus = params->nr_vcpus; - vm = memstress_create_vm(mode, nr_vcpus, params->vcpu_memory_bytes, 1, + vm = memstress_create_vm(mode, nr_vcpus, params->vcpu_memory_bytes, + 0, 1, params->backing_src, !overlap_memory_access); memstress_start_vcpu_threads(nr_vcpus, vcpu_thread_main); diff --git a/tools/testing/selftests/kvm/demand_paging_test.c b/tools/testing/selftests/kvm/demand_paging_test.c index b0e1fc4de9e2..bc5c171eca9e 100644 --- a/tools/testing/selftests/kvm/demand_paging_test.c +++ b/tools/testing/selftests/kvm/demand_paging_test.c @@ -135,7 +135,7 @@ static void run_test(enum vm_guest_mode mode, void *arg) struct kvm_vm *vm; int i; - vm = memstress_create_vm(mode, nr_vcpus, guest_percpu_mem_size, 1, + vm = memstress_create_vm(mode, nr_vcpus, guest_percpu_mem_size, 0, 1, p->src_type, p->partition_vcpu_memory_access); demand_paging_size = get_backing_src_pagesz(p->src_type); diff --git a/tools/testing/selftests/kvm/dirty_log_perf_test.c b/tools/testing/selftests/kvm/dirty_log_perf_test.c index e9d6d1aecf89..40058fe2b58f 100644 --- a/tools/testing/selftests/kvm/dirty_log_perf_test.c +++ b/tools/testing/selftests/kvm/dirty_log_perf_test.c @@ -133,6 +133,7 @@ struct test_params { int slots; uint32_t write_percent; uint32_t random_seed; + uint64_t samples_per_vcpu; bool random_access; }; @@ -224,6 +225,7 @@ static void run_test(enum vm_guest_mode mode, void *arg) int i; vm = memstress_create_vm(mode, nr_vcpus, guest_percpu_mem_size, + p->samples_per_vcpu, p->slots, p->backing_src, p->partition_vcpu_memory_access); @@ -274,6 +276,7 @@ static void run_test(enum vm_guest_mode mode, void *arg) ts_diff = timespec_elapsed(start); pr_info("Populate memory time: %ld.%.9lds\n", ts_diff.tv_sec, ts_diff.tv_nsec); + memstress_print_percentiles(vm, nr_vcpus); /* Enable dirty logging */ clock_gettime(CLOCK_MONOTONIC, &start); @@ -304,6 +307,7 @@ static void run_test(enum vm_guest_mode mode, void *arg) vcpu_dirty_total = timespec_add(vcpu_dirty_total, ts_diff); pr_info("Iteration %d dirty memory time: %ld.%.9lds\n", iteration, ts_diff.tv_sec, ts_diff.tv_nsec); + memstress_print_percentiles(vm, nr_vcpus); clock_gettime(CLOCK_MONOTONIC, &start); get_dirty_log(vm, bitmaps, p->slots); @@ -428,6 +432,7 @@ int main(int argc, char *argv[]) .slots = 1, .random_seed = 1, .write_percent = 100, + .samples_per_vcpu = 1000, }; int opt; @@ -438,7 +443,7 @@ int main(int argc, char *argv[]) guest_modes_append_default(); - while ((opt = getopt(argc, argv, "ab:c:eghi:m:nop:r:s:v:x:w:")) != -1) { + while ((opt = getopt(argc, argv, "ab:c:eghi:m:nop:r:s:S:v:x:w:")) != -1) { switch (opt) { case 'a': p.random_access = true; @@ -480,6 +485,9 @@ int main(int argc, char *argv[]) case 's': p.backing_src = parse_backing_src_type(optarg); break; + case 'S': + p.samples_per_vcpu = atoi_positive("Number of samples/vcpu", optarg); + break; case 'v': nr_vcpus = atoi_positive("Number of vCPUs", optarg); TEST_ASSERT(nr_vcpus <= max_vcpus, diff --git a/tools/testing/selftests/kvm/include/memstress.h b/tools/testing/selftests/kvm/include/memstress.h index 72e3e358ef7b..25a3b5e308e9 100644 --- a/tools/testing/selftests/kvm/include/memstress.h +++ b/tools/testing/selftests/kvm/include/memstress.h @@ -37,6 +37,12 @@ struct memstress_args { uint64_t guest_page_size; uint32_t random_seed; uint32_t write_percent; + uint64_t samples_per_vcpu; + /* Store all samples in a flat array so they can be easily + * sorted later. + */ + vm_vaddr_t latency_samples; + /* Run vCPUs in L2 instead of L1, if the architecture supports it. */ bool nested; @@ -56,7 +62,8 @@ struct memstress_args { extern struct memstress_args memstress_args; struct kvm_vm *memstress_create_vm(enum vm_guest_mode mode, int nr_vcpus, - uint64_t vcpu_memory_bytes, int slots, + uint64_t vcpu_memory_bytes, + uint64_t samples_per_vcpu, int slots, enum vm_mem_backing_src_type backing_src, bool partition_vcpu_memory_access); void memstress_destroy_vm(struct kvm_vm *vm); @@ -72,4 +79,5 @@ void memstress_guest_code(uint32_t vcpu_id); uint64_t memstress_nested_pages(int nr_vcpus); void memstress_setup_nested(struct kvm_vm *vm, int nr_vcpus, struct kvm_vcpu *vcpus[]); +void memstress_print_percentiles(struct kvm_vm *vm, int nr_vcpus); #endif /* SELFTEST_KVM_MEMSTRESS_H */ diff --git a/tools/testing/selftests/kvm/lib/memstress.c b/tools/testing/selftests/kvm/lib/memstress.c index 5f1d3173c238..c275471ad6d8 100644 --- a/tools/testing/selftests/kvm/lib/memstress.c +++ b/tools/testing/selftests/kvm/lib/memstress.c @@ -48,14 +48,17 @@ void memstress_guest_code(uint32_t vcpu_idx) { struct memstress_args *args = &memstress_args; struct memstress_vcpu_args *vcpu_args = &args->vcpu_args[vcpu_idx]; - struct guest_random_state rand_state; uint64_t gva; uint64_t pages; uint64_t addr; uint64_t page; int i; - - rand_state = new_guest_random_state(args->random_seed + vcpu_idx); + struct guest_random_state rand_state = + new_guest_random_state(args->random_seed + vcpu_idx); + uint64_t *vcpu_samples = (uint64_t *)args->latency_samples + + args->samples_per_vcpu * vcpu_idx; + uint64_t cycles; + uint32_t maybe_sample; gva = vcpu_args->gva; pages = vcpu_args->pages; @@ -73,15 +76,46 @@ void memstress_guest_code(uint32_t vcpu_idx) addr = gva + (page * args->guest_page_size); if (guest_random_u32(&rand_state) % 100 < args->write_percent) - *(uint64_t *)addr = 0x0123456789ABCDEF; + cycles = MEASURE_CYCLES(*(uint64_t *)addr = 0x0123456789ABCDEF); else - READ_ONCE(*(uint64_t *)addr); + cycles = MEASURE_CYCLES(READ_ONCE(*(uint64_t *)addr)); + + if (i < args->samples_per_vcpu) { + vcpu_samples[i] = cycles; + continue; + } + + maybe_sample = guest_random_u32(&rand_state) % (i + 1); + + if (maybe_sample < args->samples_per_vcpu) + vcpu_samples[maybe_sample] = cycles; } GUEST_SYNC(1); } } +/* compare function for qsort */ +static int memstress_qcmp(const void *a, const void *b) +{ + return *(int *)a - *(int *)b; +} + +void memstress_print_percentiles(struct kvm_vm *vm, int nr_vcpus) +{ + uint64_t n_samples = nr_vcpus * memstress_args.samples_per_vcpu; + uint64_t *host_latency_samples = addr_gva2hva(vm, memstress_args.latency_samples); + + qsort(host_latency_samples, n_samples, sizeof(uint64_t), &memstress_qcmp); + + pr_info("Latency distribution (ns) = min:%6.0lf, 50th:%6.0lf, 90th:%6.0lf, 99th:%6.0lf, max:%6.0lf\n", + cycles_to_ns(vcpus[0], (double)host_latency_samples[0]), + cycles_to_ns(vcpus[0], (double)host_latency_samples[n_samples / 2]), + cycles_to_ns(vcpus[0], (double)host_latency_samples[n_samples * 9 / 10]), + cycles_to_ns(vcpus[0], (double)host_latency_samples[n_samples * 99 / 100]), + cycles_to_ns(vcpus[0], (double)host_latency_samples[n_samples - 1])); +} + void memstress_setup_vcpus(struct kvm_vm *vm, int nr_vcpus, struct kvm_vcpu *vcpus[], uint64_t vcpu_memory_bytes, @@ -119,21 +153,26 @@ void memstress_setup_vcpus(struct kvm_vm *vm, int nr_vcpus, } struct kvm_vm *memstress_create_vm(enum vm_guest_mode mode, int nr_vcpus, - uint64_t vcpu_memory_bytes, int slots, + uint64_t vcpu_memory_bytes, + uint64_t samples_per_vcpu, int slots, enum vm_mem_backing_src_type backing_src, bool partition_vcpu_memory_access) { struct memstress_args *args = &memstress_args; struct kvm_vm *vm; - uint64_t guest_num_pages, slot0_pages = 0; + uint64_t guest_num_pages, sample_pages, slot0_pages = 0; uint64_t backing_src_pagesz = get_backing_src_pagesz(backing_src); uint64_t region_end_gfn; + uint64_t sample_size; + uint64_t sample_slot; + uint64_t sample_start; int i; pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode)); /* By default vCPUs will write to memory. */ args->write_percent = 100; + args->samples_per_vcpu = samples_per_vcpu; /* * Snapshot the non-huge page size. This is used by the guest code to @@ -159,12 +198,17 @@ struct kvm_vm *memstress_create_vm(enum vm_guest_mode mode, int nr_vcpus, if (args->nested) slot0_pages += memstress_nested_pages(nr_vcpus); + sample_size = samples_per_vcpu * nr_vcpus * sizeof(uint64_t); + sample_pages = vm_adjust_num_guest_pages( + mode, 1 + sample_size / args->guest_page_size); + /* * Pass guest_num_pages to populate the page tables for test memory. * The memory is also added to memslot 0, but that's a benign side * effect as KVM allows aliasing HVAs in meslots. */ - vm = __vm_create_with_vcpus(mode, nr_vcpus, slot0_pages + guest_num_pages, + vm = __vm_create_with_vcpus(mode, nr_vcpus, + slot0_pages + guest_num_pages + sample_pages, memstress_guest_code, vcpus); args->vm = vm; @@ -190,7 +234,7 @@ struct kvm_vm *memstress_create_vm(enum vm_guest_mode mode, int nr_vcpus, " nr_vcpus: %d wss: %" PRIx64 "]\n", guest_num_pages, region_end_gfn - 1, nr_vcpus, vcpu_memory_bytes); - args->gpa = (region_end_gfn - guest_num_pages - 1) * args->guest_page_size; + args->gpa = (region_end_gfn - guest_num_pages - sample_pages - 1) * args->guest_page_size; args->gpa = align_down(args->gpa, backing_src_pagesz); #ifdef __s390x__ /* Align to 1M (segment size) */ @@ -213,6 +257,12 @@ struct kvm_vm *memstress_create_vm(enum vm_guest_mode mode, int nr_vcpus, /* Do mapping for the demand paging memory slot */ virt_map(vm, guest_test_virt_mem, args->gpa, guest_num_pages); + memstress_args.latency_samples = guest_test_virt_mem + args->size; + sample_start = args->gpa + args->size; + sample_slot = MEMSTRESS_MEM_SLOT_INDEX + slots; + vm_userspace_mem_region_add(vm, backing_src, sample_start, sample_slot, sample_pages, 0); + virt_map(vm, memstress_args.latency_samples, sample_start, sample_pages); + memstress_setup_vcpus(vm, nr_vcpus, vcpus, vcpu_memory_bytes, partition_vcpu_memory_access); diff --git a/tools/testing/selftests/kvm/memslot_modification_stress_test.c b/tools/testing/selftests/kvm/memslot_modification_stress_test.c index 9855c41ca811..0a14f7d16e0c 100644 --- a/tools/testing/selftests/kvm/memslot_modification_stress_test.c +++ b/tools/testing/selftests/kvm/memslot_modification_stress_test.c @@ -95,7 +95,7 @@ static void run_test(enum vm_guest_mode mode, void *arg) struct test_params *p = arg; struct kvm_vm *vm; - vm = memstress_create_vm(mode, nr_vcpus, guest_percpu_mem_size, 1, + vm = memstress_create_vm(mode, nr_vcpus, guest_percpu_mem_size, 0, 1, VM_MEM_SRC_ANONYMOUS, p->partition_vcpu_memory_access);