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Re: [PATCH] aarch64: optimized memcpy implementation for thunderx2


This seems like your first contribution to glibc, Welcome! Can you (or one of the stewards) please let us know if you have signed the FSF copyright assignment for glibc? That is necessary for any contributions to be included into glibc. In general, please review the Contribution Checklist[1] to understand the prerequisites for contributing patches to glibc.

On 28/09/18 11:38 PM, Anton Youdkevitch wrote:
Optimized memcpy implementation using "ext" instruction. The
speedup is up to 30% on larger lengths comparing to the existing
thunderx2 implementation. Performance comparison is done using
the standard lib's benchmarks.

Could you please name the microbenchmarks you've used to make the comparison. That is, have you checked memcpy-large or memcpy-walk? Given that typically large copies are uncached, I would trust memcpy-walk more than memcpy-large for them because in the latter case the instruction costs will tend to dominate over the cost of load from memory, which is not very useful for large copies.

Also, (and this is a personal nit so you don't have to take it seriously) it would be really nice if the patch is inline and not an attachment since that allows me to respond to the patch contents inline :)



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