Add kunit tests to benchmark 256MiB copies to a KVEC iterator, a BVEC iterator, an XARRAY iterator and to a loop that allocates 256-page BVECs and fills them in (similar to a maximal bio struct being set up).
Signed-off-by: David Howells dhowells@redhat.com cc: Christoph Hellwig hch@lst.de cc: Christian Brauner brauner@kernel.org cc: Jens Axboe axboe@kernel.dk cc: Al Viro viro@zeniv.linux.org.uk cc: David Hildenbrand david@redhat.com cc: John Hubbard jhubbard@nvidia.com cc: Brendan Higgins brendanhiggins@google.com cc: David Gow davidgow@google.com cc: linux-kselftest@vger.kernel.org cc: kunit-dev@googlegroups.com cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org --- lib/kunit_iov_iter.c | 251 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 251 insertions(+)
diff --git a/lib/kunit_iov_iter.c b/lib/kunit_iov_iter.c index 0b7961bbab62..f8d0cd6a2923 100644 --- a/lib/kunit_iov_iter.c +++ b/lib/kunit_iov_iter.c @@ -1241,6 +1241,253 @@ static void __init iov_kunit_extract_pages_xarray(struct kunit *test) KUNIT_SUCCEED(); }
+static void iov_kunit_free_page(void *data) +{ + __free_page(data); +} + +#define IOV_KUNIT_NR_SAMPLES 16 +static void __init iov_kunit_benchmark_print_stats(struct kunit *test, + unsigned int *samples) +{ + unsigned long long sumsq = 0; + unsigned long total = 0, mean, stddev; + unsigned int n = IOV_KUNIT_NR_SAMPLES; + int i; + + //for (i = 0; i < n; i++) + // kunit_info(test, "run %x: %u uS\n", i, samples[i]); + + /* Ignore the 0th sample as that may include extra overhead such as + * setting up PTEs. + */ + samples++; + n--; + for (i = 0; i < n; i++) + total += samples[i]; + mean = total / n; + + for (i = 0; i < n; i++) { + long s = samples[i] - mean; + + sumsq += s * s; + } + stddev = int_sqrt64(sumsq); + + kunit_info(test, "avg %lu uS, stddev %lu uS\n", mean, stddev); +} + +/* + * Create a source buffer for benchmarking. + */ +static void *__init iov_kunit_create_source(struct kunit *test, size_t npages) +{ + struct page *page, **pages; + void *scratch; + size_t i; + + /* Allocate a page and tile it repeatedly in the buffer. */ + page = alloc_page(GFP_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, page); + kunit_add_action_or_reset(test, iov_kunit_free_page, page); + + pages = kunit_kmalloc_array(test, npages, sizeof(pages[0]), GFP_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, pages); + for (i = 0; i < npages; i++) { + pages[i] = page; + get_page(page); + } + + scratch = vmap(pages, npages, VM_MAP | VM_MAP_PUT_PAGES, PAGE_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, scratch); + kunit_add_action_or_reset(test, iov_kunit_unmap, scratch); + return scratch; +} + +/* + * Time copying 256MiB through an ITER_KVEC. + */ +static void __init iov_kunit_benchmark_kvec(struct kunit *test) +{ + struct iov_iter iter; + struct kvec kvec[8]; + unsigned int samples[IOV_KUNIT_NR_SAMPLES]; + ktime_t a, b; + ssize_t copied; + size_t size = 256 * 1024 * 1024, npages = size / PAGE_SIZE, part; + void *scratch, *buffer; + int i; + + /* Allocate a huge buffer and populate it with pages. */ + buffer = iov_kunit_create_source(test, npages); + + /* Create a single large buffer to copy to/from. */ + scratch = iov_kunit_create_source(test, npages); + + /* Split the target over a number of kvecs */ + copied = 0; + for (i = 0; i < ARRAY_SIZE(kvec); i++) { + part = size / ARRAY_SIZE(kvec); + kvec[i].iov_base = buffer + copied; + kvec[i].iov_len = part; + copied += part; + } + kvec[i - 1].iov_len += size - part; + + /* Perform and time a bunch of copies. */ + kunit_info(test, "Benchmarking copy_to_iter() over KVEC:\n"); + for (i = 0; i < IOV_KUNIT_NR_SAMPLES; i++) { + iov_iter_kvec(&iter, ITER_DEST, kvec, ARRAY_SIZE(kvec), size); + + a = ktime_get_real(); + copied = copy_to_iter(scratch, size, &iter); + b = ktime_get_real(); + KUNIT_EXPECT_EQ(test, copied, size); + samples[i] = ktime_to_us(ktime_sub(b, a)); + } + + iov_kunit_benchmark_print_stats(test, samples); + KUNIT_SUCCEED(); +} + +/* + * Time copying 256MiB through an ITER_BVEC. + */ +static void __init iov_kunit_benchmark_bvec(struct kunit *test) +{ + struct iov_iter iter; + struct bio_vec *bvec; + struct page *page; + unsigned int samples[IOV_KUNIT_NR_SAMPLES]; + ktime_t a, b; + ssize_t copied; + size_t size = 256 * 1024 * 1024, npages = size / PAGE_SIZE; + void *scratch; + int i; + + /* Allocate a page and tile it repeatedly in the buffer. */ + page = alloc_page(GFP_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, page); + kunit_add_action_or_reset(test, iov_kunit_free_page, page); + + bvec = kunit_kmalloc_array(test, npages, sizeof(bvec[0]), GFP_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, bvec); + for (i = 0; i < npages; i++) + bvec_set_page(&bvec[i], page, PAGE_SIZE, 0); + + /* Create a single large buffer to copy to/from. */ + scratch = iov_kunit_create_source(test, npages); + + /* Perform and time a bunch of copies. */ + kunit_info(test, "Benchmarking copy_to_iter() over BVEC:\n"); + for (i = 0; i < IOV_KUNIT_NR_SAMPLES; i++) { + iov_iter_bvec(&iter, ITER_DEST, bvec, npages, size); + a = ktime_get_real(); + copied = copy_to_iter(scratch, size, &iter); + b = ktime_get_real(); + KUNIT_EXPECT_EQ(test, copied, size); + samples[i] = ktime_to_us(ktime_sub(b, a)); + } + + iov_kunit_benchmark_print_stats(test, samples); + KUNIT_SUCCEED(); +} + +/* + * Time copying 256MiB through an ITER_BVEC in 256 page chunks. + */ +static void __init iov_kunit_benchmark_bvec_split(struct kunit *test) +{ + struct iov_iter iter; + struct bio_vec *bvec; + struct page *page; + unsigned int samples[IOV_KUNIT_NR_SAMPLES]; + ktime_t a, b; + ssize_t copied; + size_t size, npages = 64; + void *scratch; + int i, j; + + /* Allocate a page and tile it repeatedly in the buffer. */ + page = alloc_page(GFP_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, page); + kunit_add_action_or_reset(test, iov_kunit_free_page, page); + + /* Create a single large buffer to copy to/from. */ + scratch = iov_kunit_create_source(test, npages); + + /* Perform and time a bunch of copies. */ + kunit_info(test, "Benchmarking copy_to_iter() over BVEC:\n"); + for (i = 0; i < IOV_KUNIT_NR_SAMPLES; i++) { + size = 256 * 1024 * 1024; + a = ktime_get_real(); + do { + size_t part = min(size, npages * PAGE_SIZE); + + bvec = kunit_kmalloc_array(test, npages, sizeof(bvec[0]), GFP_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, bvec); + for (j = 0; j < npages; j++) + bvec_set_page(&bvec[j], page, PAGE_SIZE, 0); + + iov_iter_bvec(&iter, ITER_DEST, bvec, npages, part); + copied = copy_to_iter(scratch, part, &iter); + KUNIT_EXPECT_EQ(test, copied, part); + size -= part; + } while (size > 0); + b = ktime_get_real(); + samples[i] = ktime_to_us(ktime_sub(b, a)); + } + + iov_kunit_benchmark_print_stats(test, samples); + KUNIT_SUCCEED(); +} + +/* + * Time copying 256MiB through an ITER_XARRAY. + */ +static void __init iov_kunit_benchmark_xarray(struct kunit *test) +{ + struct iov_iter iter; + struct xarray *xarray; + struct page *page; + unsigned int samples[IOV_KUNIT_NR_SAMPLES]; + ktime_t a, b; + ssize_t copied; + size_t size = 256 * 1024 * 1024, npages = size / PAGE_SIZE; + void *scratch; + int i; + + /* Allocate a page and tile it repeatedly in the buffer. */ + page = alloc_page(GFP_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, page); + kunit_add_action_or_reset(test, iov_kunit_free_page, page); + + xarray = iov_kunit_create_xarray(test); + + for (i = 0; i < npages; i++) { + void *x = xa_store(xarray, i, page, GFP_KERNEL); + + KUNIT_ASSERT_FALSE(test, xa_is_err(x)); + } + + /* Create a single large buffer to copy to/from. */ + scratch = iov_kunit_create_source(test, npages); + + /* Perform and time a bunch of copies. */ + kunit_info(test, "Benchmarking copy_to_iter() over XARRAY:\n"); + for (i = 0; i < IOV_KUNIT_NR_SAMPLES; i++) { + iov_iter_xarray(&iter, ITER_DEST, xarray, 0, size); + a = ktime_get_real(); + copied = copy_to_iter(scratch, size, &iter); + b = ktime_get_real(); + KUNIT_EXPECT_EQ(test, copied, size); + samples[i] = ktime_to_us(ktime_sub(b, a)); + } + + iov_kunit_benchmark_print_stats(test, samples); + KUNIT_SUCCEED(); +} + static struct kunit_case __refdata iov_kunit_cases[] = { KUNIT_CASE(iov_kunit_copy_to_ubuf), KUNIT_CASE(iov_kunit_copy_from_ubuf), @@ -1257,6 +1504,10 @@ static struct kunit_case __refdata iov_kunit_cases[] = { KUNIT_CASE(iov_kunit_extract_pages_kvec), KUNIT_CASE(iov_kunit_extract_pages_bvec), KUNIT_CASE(iov_kunit_extract_pages_xarray), + KUNIT_CASE(iov_kunit_benchmark_kvec), + KUNIT_CASE(iov_kunit_benchmark_bvec), + KUNIT_CASE(iov_kunit_benchmark_bvec_split), + KUNIT_CASE(iov_kunit_benchmark_xarray), {} };