Re: [linus:master] [iov_iter] c9eec08bac: vm-scalability.throughput -16.9% regression

David Howells
2023-11-16T16:44:15Z

Borislav Petkov <bp@alien8.de> wrote:

> diff --git a/Makefile b/Makefile
> index ede0bd241056..94d93070d54a 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -996,6 +996,8 @@ endif
> # change __FILE__ to the relative path from the srctree
> KBUILD_CPPFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=)
>
> +KBUILD_CFLAGS += $(call cc-option,-mstringop-strategy=libcall)
> +
> # include additional Makefiles when needed
> include-y := scripts/Makefile.extrawarn
> include-$(CONFIG_DEBUG_INFO) += scripts/Makefile.debug

If you wanted this patch trying, I get the following numbers:

iov_kunit_benchmark_bvec: avg 9950 uS, stddev 40 uS
iov_kunit_benchmark_bvec: avg 9950 uS, stddev 53 uS
iov_kunit_benchmark_bvec: avg 9973 uS, stddev 69 uS
iov_kunit_benchmark_bvec_split: avg 9793 uS, stddev 28 uS
iov_kunit_benchmark_bvec_split: avg 9800 uS, stddev 41 uS
iov_kunit_benchmark_bvec_split: avg 9804 uS, stddev 16 uS
iov_kunit_benchmark_kvec: avg 10122 uS, stddev 4403 uS
iov_kunit_benchmark_kvec: avg 9757 uS, stddev 1516 uS
iov_kunit_benchmark_kvec: avg 9909 uS, stddev 2694 uS
iov_kunit_benchmark_xarray: avg 10526 uS, stddev 52 uS
iov_kunit_benchmark_xarray: avg 10529 uS, stddev 48 uS
iov_kunit_benchmark_xarray: avg 10532 uS, stddev 63 uS
iov_kunit_benchmark_xarray_to_bvec: avg 10468 uS, stddev 23 uS
iov_kunit_benchmark_xarray_to_bvec: avg 10469 uS, stddev 157 uS
iov_kunit_benchmark_xarray_to_bvec: avg 10471 uS, stddev 163 uS

I'm using the 6 patches here:

https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=iov-kunit

Set CONFIG_TEST_IOV_ITER=m and then load the kunit_iov_iter.ko module. It'll
dump its benchmarks to dmesg.

David