attribute: faster NewSet, NewSetWithFiltered

[akehlenbeck]

Replace a manual loop in computeDistinctReflect with a direct call to reflect.Value.Convert(). The resulting code is both simpler and faster.

The "len" parameter in the following benchmarks indicates the number of attributes in the set. Sets with ten or fewer attributes use a non-reflection-based codepath that isn't modified by this change.

goos: linux
goarch: amd64
pkg: go.opentelemetry.io/otel/attribute
cpu: AMD EPYC 7B13

name             old time/op    new time/op    delta
NewSet/len=1-8     42.8ns ± 1%    42.2ns ± 1%   -1.23%  (p=0.016 n=5+5)
NewSet/len=2-8     71.4ns ± 1%    71.5ns ± 1%     ~     (p=1.000 n=5+5)
NewSet/len=3-8      106ns ± 1%     106ns ± 2%     ~     (p=0.881 n=5+5)
NewSet/len=4-8      127ns ± 1%     129ns ± 2%   +1.49%  (p=0.016 n=5+5)
NewSet/len=5-8      161ns ± 2%     157ns ± 2%   -1.94%  (p=0.024 n=5+5)
NewSet/len=6-8      187ns ± 1%     188ns ± 1%     ~     (p=0.460 n=5+5)
NewSet/len=7-8      212ns ± 3%     212ns ± 1%     ~     (p=0.952 n=5+5)
NewSet/len=8-8      237ns ± 2%     237ns ± 2%     ~     (p=1.000 n=5+5)
NewSet/len=9-8      265ns ± 1%     265ns ± 1%     ~     (p=0.841 n=5+5)
NewSet/len=10-8     291ns ± 1%     289ns ± 1%     ~     (p=0.143 n=5+5)
NewSet/len=11-8     666ns ± 4%     384ns ± 1%  -42.31%  (p=0.008 n=5+5)
NewSet/len=12-8     711ns ± 1%     414ns ± 1%  -41.73%  (p=0.008 n=5+5)
NewSet/len=13-8     752ns ± 1%     437ns ± 1%  -41.90%  (p=0.008 n=5+5)
NewSet/len=14-8     818ns ± 2%     464ns ± 1%  -43.29%  (p=0.008 n=5+5)
NewSet/len=15-8     866ns ± 1%     483ns ± 0%  -44.21%  (p=0.008 n=5+5)
NewSet/len=16-8     914ns ± 1%     522ns ± 3%  -42.89%  (p=0.008 n=5+5)
NewSet/len=17-8     980ns ± 2%     536ns ± 1%  -45.34%  (p=0.008 n=5+5)
NewSet/len=18-8    1.06µs ± 2%    0.58µs ± 1%  -45.54%  (p=0.008 n=5+5)
NewSet/len=19-8    1.07µs ± 1%    0.59µs ± 1%  -44.49%  (p=0.008 n=5+5)
NewSet/len=20-8    1.11µs ± 1%    0.63µs ± 1%  -43.33%  (p=0.008 n=5+5)

name             old alloc/op   new alloc/op   delta
NewSet/len=1-8      64.0B ± 0%     64.0B ± 0%     ~     (all equal)
NewSet/len=2-8       128B ± 0%      128B ± 0%     ~     (all equal)
NewSet/len=3-8       192B ± 0%      192B ± 0%     ~     (all equal)
NewSet/len=4-8       256B ± 0%      256B ± 0%     ~     (all equal)
NewSet/len=5-8       320B ± 0%      320B ± 0%     ~     (all equal)
NewSet/len=6-8       384B ± 0%      384B ± 0%     ~     (all equal)
NewSet/len=7-8       448B ± 0%      448B ± 0%     ~     (all equal)
NewSet/len=8-8       512B ± 0%      512B ± 0%     ~     (all equal)
NewSet/len=9-8       640B ± 0%      640B ± 0%     ~     (all equal)
NewSet/len=10-8      704B ± 0%      704B ± 0%     ~     (all equal)
NewSet/len=11-8    1.54kB ± 0%    0.79kB ± 0%  -48.44%  (p=0.008 n=5+5)
NewSet/len=12-8    1.79kB ± 0%    0.92kB ± 0%  -48.66%  (p=0.008 n=5+5)
NewSet/len=13-8    1.79kB ± 0%    0.92kB ± 0%  -48.66%  (p=0.008 n=5+5)
NewSet/len=14-8    2.05kB ± 0%    1.05kB ± 0%  -48.83%  (p=0.008 n=5+5)
NewSet/len=15-8    2.05kB ± 0%    1.05kB ± 0%  -48.83%  (p=0.008 n=5+5)
NewSet/len=16-8    2.30kB ± 0%    1.18kB ± 0%  -48.96%  (p=0.008 n=5+5)
NewSet/len=17-8    2.30kB ± 0%    1.18kB ± 0%  -48.96%  (p=0.008 n=5+5)
NewSet/len=18-8    2.56kB ± 0%    1.30kB ± 0%  -49.06%  (p=0.008 n=5+5)
NewSet/len=19-8    2.56kB ± 0%    1.30kB ± 0%  -49.06%  (p=0.008 n=5+5)
NewSet/len=20-8    2.82kB ± 0%    1.43kB ± 0%  -49.15%  (p=0.008 n=5+5)

[linux-foundation-easycla[bot]]

• :x: - login: @akehlenbeck . The commit (9cbe3ad8090cd7a90e19c09f021a9f3fc48515af, 83580440d46188631b9313561359abdbae2376c6) is not authorized under a signed CLA. Please click here to be authorized. For further assistance with EasyCLA, please submit a support request ticket.

[dmathieu]

Could you use benchstat to make the benchmark more comparable ?

You also need to sign the CLA

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 81.8%. Comparing base (838643a) to head (9cbe3ad).

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #6422   +/-   ##
=====================================
  Coverage   81.8%   81.8%           
=====================================
  Files        283     283           
  Lines      24899   24895    -4     
=====================================
- Hits       20379   20377    -2     
+ Misses      4117    4116    -1     
+ Partials     403     402    -1     

see 2 files with indirect coverage changes

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[akehlenbeck]

Could you use benchstat to make the benchmark more comparable ?

The output I posted did come from benchstat, yes. Is there some other formatting mode you typically use with it?

You also need to sign the CLA

Yup, I'm waiting on my company's approvers. Will the CLA status here update automatically when they approve me?

[dmathieu]

Urgh you're right, it's my friday evening mistake.