On Fri, Apr 12, 2019 at 10:31:16AM +0800, Zhangshaokun wrote: > On 2019/2/19 7:08, Ard Biesheuvel wrote: > > It turns out that the IP checksumming code is still exercised often, > > even though one might expect that modern NICs with checksum offload > > have no use for it. However, as Lingyan points out, there are > > combinations of features where the network stack may still fall back > > to software checksumming, and so it makes sense to provide an > > optimized implementation in software as well. > > > > So provide an implementation of do_csum() in scalar assembler, which, > > unlike C, gives direct access to the carry flag, making the code run > > substantially faster. The routine uses overlapping 64 byte loads for > > all input size > 64 bytes, in order to reduce the number of branches > > and improve performance on cores with deep pipelines. > > > > On Cortex-A57, this implementation is on par with Lingyan's NEON > > implementation, and roughly 7x as fast as the generic C code. > > > > Cc: "huanglingyan (A)" <huanglingy...@huawei.com> > > Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org> > > --- > > Test code after the patch. > > Hi maintainers and Ard, > > Any update on it?
I'm waiting for Robin to come back with numbers for a C implementation. Robin -- did you get anywhere with that? Will
