On 12/17/2012 04:30 AM, Jens Axel Søgaard wrote:
2012/12/17 Ryan Culpepper <r...@cs.utah.edu>:
I'd like to make bit-vectors serializable so I can replace sql-bits with
them. I'll deprecate the current sql-bits names but keep them around for a
while.
The issue is that bit-vectors are implemented using fxvectors, which are
serializable, but simply serializing them will presumably cause errors if a
bit-vector is serialized on a 64-bit machine and deserialized on a 32-bit
machine or vice versa.
One solution would be to use bytes instead of fxvectors. The performance is
about the same as far as I could tell using the sieve benchmark.
Another option is to declare that serialization across word sizes doesn't
work for bit vectors.
Any opinions?
The sieve-benchmark works on individual bits, so it makes sense that
the performance is about the same. What happens for operations that
work on words (e.g. the popcount operation)? My intuition is that
these operations will be slower.
True, popcount takes about three times as long as it used to. With a few
additional changes, popcount on a million-bit bit-vector takes 1.1 ms
using bytes, as opposed to 0.35 ms using fxvectors. (Tested on a 64-bit
machine.)
Ryan
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