examples: add a solution to the "1 Billion Row Challenge" (#23458)

Author: syrmel

cmd/tools/modules/testing/common.v

@@ -242,6 +242,7 @@ pub fn new_test_session(_vargs string, will_compile bool) TestSession {
 			skip_files << 'examples/database/psql/customer.v'
 		}
 		$if windows {
+			skip_files << 'examples/1brc/solution/main.v' // requires mmap
 			skip_files << 'examples/database/mysql.v'
 			skip_files << 'examples/database/orm.v'
 			skip_files << 'examples/smtp/mail.v' // requires OpenSSL

examples/1brc/README.md

@@ -0,0 +1,53 @@
+# 1 Billion Row Challenge (1BRC)
+
+A solution to the [1 Billion Row Challenge](https://www.morling.dev/blog/one-billion-row-challenge/), 
+written in [the V programming language](https://vlang.io/).
+
+Read more about the challenge here: https://www.morling.dev/blog/one-billion-row-challenge/
+
+
+## Running instructions
+
+Suggested compiler options for performance: 
+
+`v -cc gcc -prod -cflags "-std=c17 -march=native -mtune=native" .`
+
+
+### Step 1: Create a measurements file
+
+Compile and run `make-samples` to create the sample file.
+
+```
+cd make-samples
+v -cc gcc -prod -cflags "-std=c17 -march=native -mtune=native" .
+./make-samples 1000000000 > ~/measurements.txt
+```
+
+NOTE: If you create a billion rows, the file will be about 12GB!
+
+### Step 2: Run (and time) the solution
+
+```
+cd solution
+v -cc gcc -prod -cflags "-std=c17 -march=native -mtune=native" .
+./solution ~/measurements.txt
+```
+
+You can time the solution using `v time`:
+
+`v time ./solution ~/measurements.txt`
+
+By default, the solution runs in a single thread. If you want to run
+parallel processing, use the `-n` parameter, for example, to run with 
+8 threads:
+
+`./solution -n 8 ~/measurements.txt`
+
+On Linux, to run one thread per core, use
+
+`./solution -n $(nproc) ~/measurements.txt`
+
+### Step 3: Improve upon the solution
+
+Make changes that improve the performance and submit them. 
+Let's show off what is possible in V!