Align allocations #230
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Align allocations #230
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For AMD64 aligned inputs can make a difference in speed. This is an example of the speed difference when inputs are unaligned/aligned: ``` BenchmarkEncode100x20x10000-32 7058 172648 ns/op 6950.57 MB/s BenchmarkEncode100x20x10000-32 8406 137911 ns/op 8701.24 MB/s ``` To facilitate this the package provides an `AllocAligned(shards, each int) [][]byte`. This will allocate a number of shards, each with the size `each`. Each shard will then be aligned to a 64 byte boundary. Each encoder also has a `AllocAligned(each int) [][]byte` as an extended interface which will return the same, but with the shard count configured in the encoder. It is not possible to re-aligned already allocated slices, for example when using `Split`. When it is not possible to write to aligned shards, you should not copy, since that is most likely much slower than using them as-is.
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For AMD64 aligned inputs can make a big speed difference.
This is an example of the speed difference when inputs are unaligned/aligned:
This is mostly the case when dealing with odd-sized shards.
To facilitate this the package provides an
AllocAligned(shards, each int) [][]byte.This will allocate a number of shards, each with the size
each.Each shard will then be aligned to a 64 byte boundary.
Each encoder also has a
AllocAligned(each int) [][]byteas an extended interface which will return the same,but with the shard count configured in the encoder.
It is not possible to re-aligned already allocated slices, for example when using
Split.When it is not possible to write to aligned shards, you should not copy to them.
Full (but rather noisy) benchmark: