Introduce a tool to aid in latency testing rather than a traditional pass/fail test. The goal is to make the test configurable to expose latency issues and make them easy to reproduce and share. Start with a basic test that performs a simple DMA map/unmap and reports the duration of each operation. Report the following four 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. Signed-off-by: Aaron Lewis --- tools/testing/selftests/vfio/Makefile | 1 + .../vfio/vfio_dma_mapping_perf_test.c | 124 ++++++++++++++++++ 2 files changed, 125 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 e6e8cb52ab03..9f620c5ef6ab 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/vfio_dma_mapping_perf_test.c b/tools/testing/selftests/vfio/vfio_dma_mapping_perf_test.c new file mode 100644 index 000000000000..87d84450fc47 --- /dev/null +++ b/tools/testing/selftests/vfio/vfio_dma_mapping_perf_test.c @@ -0,0 +1,124 @@ +// 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; + +struct iommu_mapping { + u64 pgd; + u64 p4d; + u64 pud; + u64 pmd; + u64 pte; +}; + +static void timer_start(struct timespec *start) { + clock_gettime(CLOCK_MONOTONIC, start); +} + +static double timer_elapsed_ms(struct timespec start) +{ + struct timespec end; + + clock_gettime(CLOCK_MONOTONIC, &end); + + return (double)(end.tv_sec - start.tv_sec) * MSEC_PER_SEC + + (double)(end.tv_nsec - start.tv_nsec) / NSEC_PER_MSEC; +} + +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 | (_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; + struct timespec start; + u64 unmapped; + int rc; + + timer_start(&start); + region.vaddr = mmap(NULL, size, PROT_READ | PROT_WRITE, flags, -1, 0); + printf("Completed mmap() in %.2lfms\n", timer_elapsed_ms(start)); + + /* 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; + + timer_start(&start); + iommu_map(self->iommu, ®ion); + printf("Mapped HVA %p (size %luG) at IOVA 0x%lx in %.2lfms\n", + region.vaddr, size / SZ_1G, region.iova, timer_elapsed_ms(start)); + ASSERT_EQ(region.iova, to_iova(self->device, region.vaddr)); + + timer_start(&start); + rc = __iommu_unmap(self->iommu, ®ion, &unmapped); + printf("Unmapped IOVA 0x%lx in %.2lfms\n", region.iova, timer_elapsed_ms(start)); + ASSERT_EQ(rc, 0); + ASSERT_EQ(unmapped, region.size); + + timer_start(&start); + ASSERT_TRUE(!munmap(region.vaddr, size)); + printf("Completed munmap() in %.2lfms\n", timer_elapsed_ms(start)); +} + +int main(int argc, char *argv[]) +{ + device_bdf = vfio_selftests_get_bdf(&argc, argv); + return test_harness_run(argc, argv); +} -- 2.55.0.rc0.799.gd6f94ed593-goog