From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f71.google.com (mail-oo1-f71.google.com [209.85.161.71]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 74EFF4A5C45 for ; Thu, 10 Sep 2026 15:33:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.71 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789054423; cv=none; b=Y9rOKft1N6DRWT7Mu93EiqMIcj/1pcJcfqudHx2Q0TFCrHjlEellzHYpFrdR46EdfNk5s/JAmfTihXlzd0PfNtbrlWt+IOqjU71l/qnXvvTEbKywNJbsPbWqnaRDhOA78dTCoOXjxae7sPOWoAK26ehcZ9Ni5RIBCNA4pT681H8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789054423; c=relaxed/simple; bh=VNbcmRetAjkylSs6qWgwqRBalXeAbX0lAHNJ5BRYTQ0=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=ZfBETIfY1CBIi0SmnouqjO4LWSNvnlzYTY1hgmdn50ygS2ppUwrc07mpg9G3DIhSZtX1xZhs+pYK9HhR7/FeqXCDWIi0b60XFIGnO5fj99SF5ETRh8rWxXjuT+aqWRZD1W1txXmLdOPsANZM6aTjAp9zvjpkv3dTk8EdlSV6otY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--aaronlewis.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=qtFU8xAH; arc=none smtp.client-ip=209.85.161.71 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--aaronlewis.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="qtFU8xAH" Received: by mail-oo1-f71.google.com with SMTP id 006d021491bc7-6b1a3f01d2aso9349716eaf.1 for ; Thu, 10 Sep 2026 08:33:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1789054420; x=1789659220; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=N6j+31HcfYz/+LBDb53gAZgVHeHcrXg/ZUoePPqoPwc=; b=qtFU8xAHXlmKEQORgWlYyOIKxpHt2yc45PNpohUkqRNc873pgozvgh+UlEsx+zGgeF /2K7UEgnXiY59M8kDeUm5t+MJ5RpkSrghznJ/MBTXnbPkPE4XoNCi4/MCk2VDsyJ566P zuZ6cSk39Xw2wg8Bq+353qDTWSJdZv2OlC9dwDhDL8TmiPiaprdfcKxCimhfEi60wLbv 7FafQvXCXwlBNGbQm89mBatIx2WqFDFqedj9DE81P7R9FXITULjSlE8hVxkgbQKkn1F3 D7ZIkzRdRFssry8ATvwZqD3y2e0WagUpDXm0VTjZAbL6VIrlQ2P1/WNu1Sv56z3wb+a1 Z9SA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1789054420; x=1789659220; h=content-type: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:content-type; bh=N6j+31HcfYz/+LBDb53gAZgVHeHcrXg/ZUoePPqoPwc=; b=NiF/wdTMCgG4BnXzmqqI9bM9em/kyywfdXFCWyomTLuyyYPe63hJLkl5251kOM9na0 AHFUwMwx61CdqOHTn9umwx2Q9s38DID6hK24DXg8wAbVMusRtlXAWLkvVb8CgQ3hegEz 1gIpGGmwf+89EIh7Gs+Cs3RKc5gQWd2sB14ua9KPIPg5tZ8F2DDawxgiEfmge+s5ESTT i0Ne5ElrSU+39o94d0Wv1aopq08NTGC4sL6CYvR0SETkOuyP1+DfTGFCghtzQbR/e8yW cQ+YXswSiW+tZnur0rwtwL7WJlUiy5CihWA5V//HglHx/x2g25cNClR7oZXnd86Fgqg1 VhDg== X-Gm-Message-State: AFuF++mb9lqUuCrjmODwaM1pXHxyzFQdyhVW+9AHeFueo2V8v2dmVYcA r5W5W1lKDcLgcdJtyOQkbV8r/yACfVX5ID79AhgFRAlbU1irQvQWGtnqyMoAFuVVHL78A5/gA0N UuB3Mrg5mPi2224nu6wvK5mH7y6lSw5Yx9HUhv1JtdiFDi22FehFyrLbDdESVa4Bw928cuHyxKS Y5dg2mxt/YPQRNgHJzSTlIn/eEFmfBEdyBWEdFjXlxbtKMgEYyClNcVA== X-Received: from dybtx20.prod.google.com ([2002:a05:7300:f294:b0:334:e08b:1b72]) (user=aaronlewis job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6820:88f:b0:6b1:3552:3195 with SMTP id 006d021491bc7-6b6fb3df1bamr17399240eaf.11.1789054419678; Thu, 10 Sep 2026 08:33:39 -0700 (PDT) Date: Thu, 10 Sep 2026 15:33:24 +0000 In-Reply-To: <20260910153326.3085937-1-aaronlewis@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260910153326.3085937-1-aaronlewis@google.com> X-Mailer: git-send-email 2.55.0.1003.g10538fe699-goog Message-ID: <20260910153326.3085937-3-aaronlewis@google.com> Subject: [PATCH v3 2/4] vfio: selftests: Introduce vfio_dma_mapping_perf_test From: Aaron Lewis To: kvm@vger.kernel.org Cc: alex@shazbot.org, dmatlack@google.com, jgg@nvidia.com, Aaron Lewis Content-Type: text/plain; charset="UTF-8" Introduce vfio_dma_mapping_perf_test to aid in latency testing. Rather than a traditional pass/fail test, which tends to be flaky when enforcing latency bounds, this test directly reports the latency of various stages in the mapping and unmapping process. Start with a basic test that performs a simple DMA map/unmap and tracks the duration of each operation. The test reports the following metrics: 1. Time taken by mmap(). 2. Time taken to map a DMA region. 3. Time taken to unmap a DMA region. 4. Time taken by munmap(). Subsequent commits in this series will introduce more features to allow for a wider variety of testing. To ensure consistent DMA mapping times, the test uses MAP_POPULATE when calling mmap(). This forces page faults to be handled upfront, isolating the DMA mapping times from them. Signed-off-by: Aaron Lewis --- tools/testing/selftests/vfio/Makefile | 1 + .../selftests/vfio/lib/include/libvfio.h | 31 +++++++ .../vfio/vfio_dma_mapping_perf_test.c | 90 +++++++++++++++++++ 3 files changed, 122 insertions(+) create mode 100644 tools/testing/selftests/vfio/vfio_dma_mapping_perf_test.c diff --git a/tools/testing/selftests/vfio/Makefile b/tools/testing/selftests/vfio/Makefile index 2c32c48db509..ed5856af5f9a 100644 --- a/tools/testing/selftests/vfio/Makefile +++ b/tools/testing/selftests/vfio/Makefile @@ -8,6 +8,7 @@ else CFLAGS = $(KHDR_INCLUDES) TEST_GEN_PROGS += vfio_dma_mapping_test TEST_GEN_PROGS += vfio_dma_mapping_mmio_test +TEST_GEN_PROGS += vfio_dma_mapping_perf_test TEST_GEN_PROGS += vfio_iommufd_setup_test TEST_GEN_PROGS += vfio_pci_device_test TEST_GEN_PROGS += vfio_pci_device_init_perf_test diff --git a/tools/testing/selftests/vfio/lib/include/libvfio.h b/tools/testing/selftests/vfio/lib/include/libvfio.h index 07862b470777..8496b8b4da3c 100644 --- a/tools/testing/selftests/vfio/lib/include/libvfio.h +++ b/tools/testing/selftests/vfio/lib/include/libvfio.h @@ -9,6 +9,37 @@ #include #include +#include +#include +#include + +static inline void timer_start(struct timespec *start) +{ + clock_gettime(CLOCK_MONOTONIC, start); +} + +static inline uint64_t timer_elapsed_ns(struct timespec start) +{ + struct timespec end; + + clock_gettime(CLOCK_MONOTONIC, &end); + + return (uint64_t)(end.tv_sec - start.tv_sec) * NSEC_PER_SEC + + (uint64_t)(end.tv_nsec - start.tv_nsec); +} + +#define TIME(_name, _expression) do { \ + struct timespec __start; \ + int __errno; \ + \ + timer_start(&__start); \ + _expression; \ + __errno = errno; \ + ksft_print_msg(_name " = %.2lfms\n", \ + (double)timer_elapsed_ns(__start) / NSEC_PER_MSEC); \ + errno = __errno; \ +} while (0) + /* * Return the BDF string of the device that the test should use. * diff --git a/tools/testing/selftests/vfio/vfio_dma_mapping_perf_test.c b/tools/testing/selftests/vfio/vfio_dma_mapping_perf_test.c new file mode 100644 index 000000000000..4d41fecf2372 --- /dev/null +++ b/tools/testing/selftests/vfio/vfio_dma_mapping_perf_test.c @@ -0,0 +1,90 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include + +#include + +#include "kselftest_harness.h" + +static const char *device_bdf; + +FIXTURE(vfio_dma_mapping_perf_test) { + struct iommu *iommu; + struct vfio_pci_device *device; + struct iova_allocator *iova_allocator; +}; + +FIXTURE_VARIANT(vfio_dma_mapping_perf_test) { + const char *iommu_mode; + int mmap_flags; +}; + +#define FIXTURE_VARIANT_ADD_IOMMU_MODE(_iommu_mode, _name, _mmap_flags) \ +FIXTURE_VARIANT_ADD(vfio_dma_mapping_perf_test, _iommu_mode ## _ ## _name) { \ + .iommu_mode = #_iommu_mode, \ + .mmap_flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_POPULATE | (_mmap_flags), \ +} + +FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(anonymous, 0); +FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(anonymous_hugetlb_2mb, MAP_HUGETLB | MAP_HUGE_2MB); +FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(anonymous_hugetlb_1gb, MAP_HUGETLB | MAP_HUGE_1GB); + +#undef FIXTURE_VARIANT_ADD_IOMMU_MODE + +FIXTURE_SETUP(vfio_dma_mapping_perf_test) +{ + self->iommu = iommu_init(variant->iommu_mode); + self->device = vfio_pci_device_init(device_bdf, self->iommu); + self->iova_allocator = iova_allocator_init(self->iommu); +} + +FIXTURE_TEARDOWN(vfio_dma_mapping_perf_test) +{ + iova_allocator_cleanup(self->iova_allocator); + vfio_pci_device_cleanup(self->device); + iommu_cleanup(self->iommu); +} + +TEST_F(vfio_dma_mapping_perf_test, dma_map_unmap) +{ + const u64 size = SZ_1G; + const int flags = variant->mmap_flags; + struct dma_region region; + + ksft_print_msg("mmap size = %lluG\n", (unsigned long long)(size / SZ_1G)); + + TIME("mmap", + region.vaddr = mmap(NULL, size, PROT_READ | PROT_WRITE, flags, -1, 0)); + + /* Skip the test if there aren't enough HugeTLB pages available. */ + if (flags & MAP_HUGETLB && region.vaddr == MAP_FAILED) + SKIP(return, "mmap() failed: %s (%d)\n", strerror(errno), errno); + else + ASSERT_NE(region.vaddr, MAP_FAILED); + + region.iova = iova_allocator_alloc(self->iova_allocator, size); + region.size = size; + + TIME("IOMMU map", iommu_map(self->iommu, ®ion)); + ASSERT_EQ(region.iova, to_iova(self->device, region.vaddr)); + + TIME("IOMMU unmap", iommu_unmap(self->iommu, ®ion)); + TIME("munmap", ASSERT_EQ(0, munmap(region.vaddr, size))); +} + +int main(int argc, char *argv[]) +{ + device_bdf = vfio_selftests_get_bdf(&argc, argv); + return test_harness_run(argc, argv); +} -- 2.55.0.1003.g10538fe699-goog