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This reduces allocations and greatly improves performance when circbuf is used in tight loops that work with single byte streams. Signed-off-by: Akis Kesoglou <akiskesoglou@gmail.com>
Signed-off-by: Akis Kesoglou <akiskesoglou@gmail.com>
Signed-off-by: Akis Kesoglou <akiskesoglou@gmail.com>
Some operations on the circular buffer make use of modulo arithmetic, which was implemented (not surprisingly!) with the modulo operator `%`. It turns out that the modulo operator is quite slow and therefore, on tight loops, a substantial portion of the run time may be spent on it. This commit adds a separate code path for buffers with power-of-two sizes. For these, we can implement modulo arithmetic substantially more efficiently using some bit manipulation. This is not a breaking change: the public interface is exactly the same as before. An optimized buffer is transparently created under the hood whenever the requested size is a power-of-two. The commit also adds benchmarks that perform various operations on buffers that are and that are not power-of-two-sized.
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Very nice PR. Thanks! |
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This PR contains some optimizations that we use (or plan to start using soon) in production at belena.io. To summarize, these are the main changes included here:
Bytes()(at the expense of having a second, pre-allocated buffer)Check the individual commit messages for details.
For our use case (in which we use a circular buffer on a tight loop), each of these optimizations brought considerable performance improvements.