reorganize code, little bit faster

[abeobk]

Check List:

• Tests pass (./test.sh <username> shows no differences between expected and actual outputs)
• All formatting changes by the build are committed
• Your launch script is named calculate_average_<username>.sh (make sure to match casing of your GH user name) and is executable
• Output matches that of calculate_average_baseline.sh
• For new entries, or after substantial changes: When implementing custom hash structures, please point to where you deal with hash collisions (line number)

Standard set
Benchmark 1: ./calculate_average_abeobk.sh
Time (mean ± σ): 736.2 ms ± 17.3 ms [User: 18932.3 ms, System: 722.9 ms]
Range (min … max): 716.6 ms … 767.5 ms 10 runs

10k set
Benchmark 1: ./calculate_average_abeobk.sh
Time (mean ± σ): 1.848 s ± 0.022 s [User: 49.804 s, System: 0.985 s]
Range (min … max): 1.816 s … 1.889 s 10 runs

[gunnarmorling]

Just to be sure: does your implementation guarantee to handle collisions 100% correctly? Or can there be a (however small) risk for unhandled collisions and thus incorrect results? I suppose it's the former.

[abeobk]

Yes it is handled correctly (with the assumptions given in the 1brc description).
Since there are only10k stations at most, the hash table size is intentionally added 10000, so there is no need to mod the table size. The performance gains was achieved by using a fast + low collision mixer ( 0 collision for standard set, still low for 10k set, I had some fun tweaking this function :) ) and by removing lots of unnecessary branching.

[gunnarmorling]

Got it, thx.

[gunnarmorling]

Nice, 00:02.336 now!

Benchmark 1: timeout -v 300 ./calculate_average_abeobk.sh 2>&1
  Time (mean ± σ):      2.336 s ±  0.006 s    [User: 15.820 s, System: 0.701 s]
  Range (min … max):    2.329 s …  2.343 s    5 runs

Summary
  abeobk: trimmed mean 2.3362541187466674, raw times 2.3407769550800004,2.32911485408,2.3351161250800003,2.3429942460800004,2.3328692760800003

Leaderboard

| # | Result (m:s.ms) | Implementation     | JDK | Submitter     | Notes     |
|---|-----------------|--------------------|-----|---------------|-----------|
|   | 00:02.336 | [link](https://github.com/gunnarmorling/1brc/blob/main/src/main/java/dev/morling/onebrc/CalculateAverage_abeobk.java)| 21.0.1-graal | [Van Phu DO](https://github.com/abeobk) | GraalVM native binary |