This commit adds a tsm1 function for encoding a batch of floats into a
buffer. Further, it replaces the `bitstream` library used in the
existing encoders (and all the current decoders) with inlined bit
expressions within the encoder, significantly reducing the function call
overhead for larger batches.
The following benchmarks compare the performance of the existing
iterator based encoders, and the new batch oriented encoders. They look
at a sequential input slice and a randomly generated input slice.
name old time/op new time/op delta
EncodeFloats/10_seq 1.14µs ± 3% 0.24µs ± 3% -78.94% (p=0.000 n=10+10)
EncodeFloats/10_ran 1.69µs ± 2% 0.21µs ± 3% -87.43% (p=0.000 n=10+10)
EncodeFloats/100_seq 7.07µs ± 1% 1.72µs ± 1% -75.62% (p=0.000 n=7+9)
EncodeFloats/100_ran 15.8µs ± 4% 1.8µs ± 1% -88.60% (p=0.000 n=10+9)
EncodeFloats/1000_seq 50.2µs ± 3% 16.2µs ± 2% -67.66% (p=0.000 n=10+10)
EncodeFloats/1000_ran 174µs ± 2% 16µs ± 2% -90.77% (p=0.000 n=10+10)
name old alloc/op new alloc/op delta
EncodeFloats/10_seq 0.00B 0.00B ~ (all equal)
EncodeFloats/10_ran 0.00B 0.00B ~ (all equal)
EncodeFloats/100_seq 0.00B 0.00B ~ (all equal)
EncodeFloats/100_ran 0.00B 0.00B ~ (all equal)
EncodeFloats/1000_seq 0.00B 0.00B ~ (all equal)
EncodeFloats/1000_ran 0.00B 0.00B ~ (all equal)
name old allocs/op new allocs/op delta
EncodeFloats/10_seq 0.00 0.00 ~ (all equal)
EncodeFloats/10_ran 0.00 0.00 ~ (all equal)
EncodeFloats/100_seq 0.00 0.00 ~ (all equal)
EncodeFloats/100_ran 0.00 0.00 ~ (all equal)
EncodeFloats/1000_seq 0.00 0.00 ~ (all equal)
EncodeFloats/1000_ran 0.00 0.00 ~ (all equal)
FloatBatchDecodeAll behaves the same as the iterator-based float
decoder, returning an empty slice and no error when passed a buffer
with no encoded float values.
Fixes#10270
* APIs decode an entire byte slice of encoded data into the provided
`dst` slice
* APIs are stateless and in almost all cases avoid any allocations
* Intended to be used future batch-oriented TSM block decode APIs
* duplicated tests from original iterator-based APIs
Stuart Carnie
Edd Robinson