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Change the representation of IP to a pair of uint64s. #63
Commits on Dec 25, 2020
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Change the representation of IP to a pair of uint64s.
This allows IP manipulation operations to operate on IPs as two registers, which empirically leads to significant speedups, in particular on OOO superscalars where the two halves can be processed in parallel. You might expect that we could keep the representation as [16]byte, and do a cycle of BigEndian.Uint64+tweak+BigEndian.PutUint64, and that would compile down to efficient code. Unfortunately, due to a variety of missing optimizations in the Go compiler, that is not the case and that code turns into byte-wise operations. On the other hand, converting to a uint64 pair at construction results in efficient construction (a pair of MOVQ+BSWAPQ) and efficient twiddling operations (single-cycle arithmetic on 64-bit pairs). See also: - golang/go#41663 - golang/go#41684 - golang/go#42958 - The discussion in #63 name old time/op new time/op delta StdIPv4-8 146ns ± 2% 141ns ± 2% -3.42% (p=0.016 n=5+5) IPv4-8 120ns ± 1% 107ns ± 2% -10.65% (p=0.008 n=5+5) IPv4_inline-8 120ns ± 0% 118ns ± 1% -1.67% (p=0.016 n=4+5) StdIPv6-8 211ns ± 2% 215ns ± 1% +2.18% (p=0.008 n=5+5) IPv6-8 281ns ± 1% 252ns ± 1% -10.19% (p=0.008 n=5+5) IPv4Contains-8 11.8ns ± 4% 4.7ns ± 2% -60.00% (p=0.008 n=5+5) ParseIPv4-8 68.1ns ± 4% 78.8ns ± 1% +15.74% (p=0.008 n=5+5) ParseIPv6-8 419ns ± 1% 409ns ± 0% -2.40% (p=0.016 n=4+5) StdParseIPv4-8 73.7ns ± 1% 88.8ns ± 2% +20.50% (p=0.008 n=5+5) StdParseIPv6-8 132ns ± 2% 134ns ± 1% ~ (p=0.079 n=5+5) IPPrefixMasking/IPv4_/32-8 36.3ns ± 3% 4.8ns ± 4% -86.72% (p=0.008 n=5+5) IPPrefixMasking/IPv4_/17-8 39.0ns ± 0% 4.8ns ± 3% -87.78% (p=0.008 n=5+5) IPPrefixMasking/IPv4_/0-8 36.9ns ± 2% 4.8ns ± 4% -87.07% (p=0.008 n=5+5) IPPrefixMasking/IPv6_/128-8 32.7ns ± 1% 4.7ns ± 2% -85.47% (p=0.008 n=5+5) IPPrefixMasking/IPv6_/65-8 39.8ns ± 1% 4.7ns ± 1% -88.13% (p=0.008 n=5+5) IPPrefixMasking/IPv6_/0-8 40.7ns ± 1% 4.7ns ± 2% -88.41% (p=0.008 n=5+5) IPPrefixMasking/IPv6_zone_/128-8 136ns ± 3% 5ns ± 2% -96.53% (p=0.008 n=5+5) IPPrefixMasking/IPv6_zone_/65-8 142ns ± 2% 5ns ± 1% -96.65% (p=0.008 n=5+5) IPPrefixMasking/IPv6_zone_/0-8 143ns ± 2% 5ns ± 3% -96.67% (p=0.008 n=5+5) IPSetFuzz-8 22.7µs ± 2% 16.4µs ± 2% -27.84% (p=0.008 n=5+5) name old alloc/op new alloc/op delta StdIPv4-8 16.0B ± 0% 16.0B ± 0% ~ (all equal) IPv4-8 0.00B 0.00B ~ (all equal) IPv4_inline-8 0.00B 0.00B ~ (all equal) StdIPv6-8 16.0B ± 0% 16.0B ± 0% ~ (all equal) IPv6-8 16.0B ± 0% 16.0B ± 0% ~ (all equal) IPv4Contains-8 0.00B 0.00B ~ (all equal) ParseIPv4-8 0.00B 0.00B ~ (all equal) ParseIPv6-8 48.0B ± 0% 48.0B ± 0% ~ (all equal) StdParseIPv4-8 16.0B ± 0% 16.0B ± 0% ~ (all equal) StdParseIPv6-8 16.0B ± 0% 16.0B ± 0% ~ (all equal) IPPrefixMasking/IPv4_/32-8 0.00B 0.00B ~ (all equal) IPPrefixMasking/IPv4_/17-8 0.00B 0.00B ~ (all equal) IPPrefixMasking/IPv4_/0-8 0.00B 0.00B ~ (all equal) IPPrefixMasking/IPv6_/128-8 0.00B 0.00B ~ (all equal) IPPrefixMasking/IPv6_/65-8 0.00B 0.00B ~ (all equal) IPPrefixMasking/IPv6_/0-8 0.00B 0.00B ~ (all equal) IPPrefixMasking/IPv6_zone_/128-8 16.0B ± 0% 0.0B -100.00% (p=0.008 n=5+5) IPPrefixMasking/IPv6_zone_/65-8 16.0B ± 0% 0.0B -100.00% (p=0.008 n=5+5) IPPrefixMasking/IPv6_zone_/0-8 16.0B ± 0% 0.0B -100.00% (p=0.008 n=5+5) IPSetFuzz-8 2.60kB ± 0% 2.60kB ± 0% ~ (p=1.000 n=5+5) name old allocs/op new allocs/op delta StdIPv4-8 1.00 ± 0% 1.00 ± 0% ~ (all equal) IPv4-8 0.00 0.00 ~ (all equal) IPv4_inline-8 0.00 0.00 ~ (all equal) StdIPv6-8 1.00 ± 0% 1.00 ± 0% ~ (all equal) IPv6-8 1.00 ± 0% 1.00 ± 0% ~ (all equal) IPv4Contains-8 0.00 0.00 ~ (all equal) ParseIPv4-8 0.00 0.00 ~ (all equal) ParseIPv6-8 3.00 ± 0% 3.00 ± 0% ~ (all equal) StdParseIPv4-8 1.00 ± 0% 1.00 ± 0% ~ (all equal) StdParseIPv6-8 1.00 ± 0% 1.00 ± 0% ~ (all equal) IPPrefixMasking/IPv4_/32-8 0.00 0.00 ~ (all equal) IPPrefixMasking/IPv4_/17-8 0.00 0.00 ~ (all equal) IPPrefixMasking/IPv4_/0-8 0.00 0.00 ~ (all equal) IPPrefixMasking/IPv6_/128-8 0.00 0.00 ~ (all equal) IPPrefixMasking/IPv6_/65-8 0.00 0.00 ~ (all equal) IPPrefixMasking/IPv6_/0-8 0.00 0.00 ~ (all equal) IPPrefixMasking/IPv6_zone_/128-8 1.00 ± 0% 0.00 -100.00% (p=0.008 n=5+5) IPPrefixMasking/IPv6_zone_/65-8 1.00 ± 0% 0.00 -100.00% (p=0.008 n=5+5) IPPrefixMasking/IPv6_zone_/0-8 1.00 ± 0% 0.00 -100.00% (p=0.008 n=5+5) IPSetFuzz-8 33.0 ± 0% 33.0 ± 0% ~ (all equal) Signed-off-by: David Anderson <dave@natulte.net>
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