mullakhmetov / 1brc Goto Github PK

1brc challenge implementation written in C for educational purposes.

The text file has a simple structure with one measurement value per row:

Hamburg;12.0
Bulawayo;8.9
Palembang;38.8
St. John's;15.2
Cracow;12.6
...

The program should print out the min, mean, and max values per station, alphabetically ordered like so:

{Abha=5.0/18.0/27.4, Abidjan=15.7/26.0/34.1, Abéché=12.1/29.4/35.6, Accra=14.7/26.4/33.1, Addis Ababa=2.1/16.0/24.3, Adelaide=4.1/17.3/29.7, ...}

• naive linear city search (baseline) 7:09.52 total
• hashmap with linear probing 1:12.65 total
• mmap I/O + parallel workers 58.540 total
• localized thread results 23.650 total
• store city name location 16.403 total
• get city location, hash and temp in one run 14.526 total

• hashmap search
• proper output format {Abha=x/y/z, ...}
• mmap
• parallelize I/O
• custom float parsing
• profiling
• localize thread results
• avoid strcpy in hot loop
• search semicolon, newline, city location, calc hash and parse temp in one run