Re: [PATCH v4 01/13] iov_iter: Add a benchmarking kunit test

[Johannes Thumshirn]

On 13.09.23 18:58, David Howells wrote:
> ---
>   lib/kunit_iov_iter.c | 181 +++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 181 insertions(+)

Hi David,

#1 this is missing a SoB
#2 looks like all the KUNIT_ASSERT_NOT_NULL() macros are indented wrong
#3 a bit more of a commit message would be nice

Byte,
	Johannes


> 
> diff --git a/lib/kunit_iov_iter.c b/lib/kunit_iov_iter.c
> index 859b67c4d697..478fea956f58 100644
> --- a/lib/kunit_iov_iter.c
> +++ b/lib/kunit_iov_iter.c
> @@ -756,6 +756,184 @@ static void __init iov_kunit_extract_pages_xarray(struct kunit *test)
>   	KUNIT_SUCCEED();
>   }
>   
> +static void iov_kunit_free_page(void *data)
> +{
> +	__free_page(data);
> +}
> +
> +static void __init iov_kunit_benchmark_print_stats(struct kunit *test,
> +						   unsigned int *samples)
> +{
> +	unsigned long total = 0;
> +	int i;
> +
> +	for (i = 0; i < 16; i++) {
> +		total += samples[i];
> +		kunit_info(test, "run %x: %u uS\n", i, samples[i]);
> +	}
> +
> +	kunit_info(test, "avg %lu uS\n", total / 16);
> +}
> +
> +/*
> + * 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, **pages;
> +	unsigned int samples[16];
> +	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. */
> +	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;
> +
> +	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);
> +
> +	/* Perform and time a bunch of copies. */
> +	kunit_info(test, "Benchmarking copy_to_iter() over BVEC:\n");
> +	for (i = 0; i < 16; 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, **pages;
> +	unsigned int samples[16];
> +	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. */
> +	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;
> +
> +	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);
> +
> +	/* Perform and time a bunch of copies. */
> +	kunit_info(test, "Benchmarking copy_to_iter() over BVEC:\n");
> +	for (i = 0; i < 16; 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, **pages;
> +	unsigned int samples[16];
> +	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. */
> +	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;
> +
> +	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);
> +
> +	/* Perform and time a bunch of copies. */
> +	kunit_info(test, "Benchmarking copy_to_iter() over XARRAY:\n");
> +	for (i = 0; i < 16; 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_kvec),
>   	KUNIT_CASE(iov_kunit_copy_from_kvec),
> @@ -766,6 +944,9 @@ 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_bvec),
> +	KUNIT_CASE(iov_kunit_benchmark_bvec_split),
> +	KUNIT_CASE(iov_kunit_benchmark_xarray),
>   	{}
>   };
>   
> 
>