diff --git a/README.md b/README.md
index 1427160..6c1a56e 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 # langs-performance
-C++ vs. Python vs. Perl vs. PHP vs. Java vs. NodeJS vs. Go vs. Ruby performance benchmark
+C++ vs. Python vs. Perl vs. PHP vs. Java vs. NodeJS vs. Go vs. Ruby vs. Rust vs. Swift performance benchmark
 
 Blog articles:
 * 2016: https://blog.famzah.net/2016/09/10/cpp-vs-python-vs-php-vs-java-vs-others-performance-benchmark-2016-q3/
diff --git a/primes.swift b/primes.swift
new file mode 100644
index 0000000..8b594c9
--- /dev/null
+++ b/primes.swift
@@ -0,0 +1,42 @@
+import Foundation
+
+func get_primes7(_ n: Int) -> [Int] {
+  if n < 2 {
+    return []
+  } else if n == 2 {
+    return [2]
+  }
+
+  // do only odd numbers starting at 3
+  var s = Array(stride(from: 3, to: n, by: 2))
+
+  let mroot: Int = Int(sqrt(Double(n)))
+  let half = s.count
+  var i = 0
+  var m = 3
+  while m <= mroot {
+    if s[i] != 0 {
+      var j: Int = (m*m - 3) / 2
+      while j < half {
+        s[j] = 0
+        j += m
+      }
+    }
+    i += 1
+    m += 2
+  }
+  return [2] + s.filter { $0 != 0 }
+}
+
+if let period_time_var = ProcessInfo.processInfo.environment["RUN_TIME"] {
+  let start_time = Date()
+  let period_time = Int(period_time_var)!
+
+  while Int(Date().timeIntervalSince(start_time)) < period_time {
+    let res = get_primes7(10_000_000)
+    print("Found \(res.count) prime numbers.")
+  }
+} else {
+  print("RUN_TIME not found.")
+}
+
diff --git a/run.sh b/run.sh
index aca7c8a..e33b1f4 100755
--- a/run.sh
+++ b/run.sh
@@ -110,10 +110,21 @@ go clean
 
 ##
 
+C='swiftc' ; SRC='primes.swift'  ; run_benchmark 'Swift (optimized with -O)' \
+	"$C $SRC -o primes.swift.out -O -swift-version 4" './primes.swift.out' "$C -version" 'head -n1' "$SRC"
+rm -f ./primes.swift.out
+
+C='swiftc' ; SRC='primes.swift'  ; run_benchmark 'Swift (not optimized)' \
+	"$C $SRC -o primes.swift.out -swift-version 4" './primes.swift.out' "$C -version" 'head -n1' "$SRC"
+rm -f ./primes.swift.out
+
+##
+
 C='pypy'      ; SRC='primes.py'  ; run_benchmark 'Python 2.7 + PyPy' 'true' "$C $SRC" "$C -V" 'cat' "$SRC"
 C='python2.7' ; SRC='primes.py'  ; run_benchmark 'Python 2.7' 'true' "$C $SRC" "$C -V" 'cat' "$SRC"
 C='python3.2' ; SRC='primes.py'  ; run_benchmark 'Python 3.2' 'true' "$C $SRC" "$C -V" 'cat' "$SRC"
 C='python3.5' ; SRC='primes.py'  ; run_benchmark 'Python 3.5' 'true' "$C $SRC" "$C -V" 'cat' "$SRC"
+C='python3.6' ; SRC='primes.py'  ; run_benchmark 'Python 3.6' 'true' "$C $SRC" "$C -V" 'cat' "$SRC"
 
 ##