diff --git a/tools/vrepl.v b/tools/vrepl.v
index ad885fbe0e..a14ad511e7 100644
--- a/tools/vrepl.v
+++ b/tools/vrepl.v
@@ -8,6 +8,8 @@ import (
 	os
 	term
 	readline
+	os.cmdline
+	filepath
 )
 
 struct Repl {
@@ -71,13 +73,14 @@ pub fn repl_help() {
 ')
 }
 
-pub fn run_repl() []string {
+pub fn run_repl(workdir string, vrepl_prefix string) []string {
 	version := v_version()
 	println(version)
 	println('Use Ctrl-C or `exit` to exit')
-	file := '.vrepl.v'
-	temp_file := '.vrepl_temp.v'
-	mut prompt := '>>> '
+	
+	file := filepath.join( workdir, '.${vrepl_prefix}vrepl.v' )
+	temp_file := filepath.join( workdir, '.${vrepl_prefix}vrepl_temp.v')	
+	mut prompt := '>>> '	
 	defer {
 		os.rm(file)
 		os.rm(temp_file)
@@ -192,14 +195,20 @@ pub fn run_repl() []string {
 fn print_output(s os.Result) {
 	lines := s.output.split('\n')
 	for line in lines {
-		if line.starts_with('.vrepl_temp.v') {
+		if line.contains('.vrepl_temp.v:') {
 			// Hide the temporary file name
-			idx := line.index(' ') or {
-				println(line)
+			sline := line.all_after('.vrepl_temp.v:')
+			idx := sline.index(' ') or {
+				println(sline)
 				return
 			}
-			println(line[idx+1..])
-		}	 else {
+			println(sline[idx+1..])
+		} else if line.contains('.vrepl.v:') {
+			// Ensure that .vrepl.v: is at the start, ignore the path
+			// This is needed to have stable .repl tests.
+			idx := line.index('.vrepl.v:') or { return }
+			println(line[idx..])
+		} else {
 			println(line)
 		}
 	}
@@ -207,13 +216,20 @@ fn print_output(s os.Result) {
 }
 
 fn main() {
+	// Support for the parameters replfolder and replprefix is needed
+	// so that the repl can be launched in parallel by several different
+	// threads by the REPL test runner.
+	args := cmdline.after(os.args, ['repl'])
+	replfolder := os.realpath( cmdline.option(args, '-replfolder', '.') )
+	replprefix := cmdline.option(args, '-replprefix', 'noprefix.')
+	os.chdir( replfolder )
 	if !os.exists(os.getenv('VEXE')) {
 		println('Usage:')
 		println('  VEXE=vexepath vrepl\n')
 		println('  ... where vexepath is the full path to the v executable file')
 		return
 	}
-	run_repl()
+	run_repl( replfolder, replprefix )
 }
 
 pub fn rerror(s string) {
diff --git a/vlib/compiler/tests/repl/repl_test.v b/vlib/compiler/tests/repl/repl_test.v
index dfd2b492be..107f7ff83c 100644
--- a/vlib/compiler/tests/repl/repl_test.v
+++ b/vlib/compiler/tests/repl/repl_test.v
@@ -3,6 +3,9 @@ module main
 import os
 import compiler.tests.repl.runner
 import benchmark
+import runtime
+import sync
+import filepath
 
 fn test_the_v_compiler_can_be_invoked() {
 	vexec := runner.full_path_to_v(5)
@@ -23,21 +26,79 @@ fn test_the_v_compiler_can_be_invoked() {
 	assert r_error.output == '`nonexisting.v` does not exist'
 }
 
+struct Session {
+mut:
+	options   runner.RunnerOptions
+	bmark     benchmark.Benchmark
+	ntask     int
+	ntask_mtx &sync.Mutex
+	waitgroup &sync.WaitGroup
+}
+
 fn test_all_v_repl_files() {
-	options := runner.new_options()
-	mut bmark := benchmark.new_benchmark()
-	for file in options.files {
-		bmark.step()
-		fres := runner.run_repl_file(options.wd, options.vexec, file) or {
-			bmark.fail()
-			eprintln(bmark.step_message_fail(err))
+	mut session := &Session{
+		options: runner.new_options()
+		bmark: benchmark.new_benchmark()
+		ntask: 0
+		ntask_mtx: sync.new_mutex()
+		waitgroup: sync.new_waitgroup()
+	}
+
+	// warmup, and ensure that the vrepl is compiled in single threaded mode if it does not exist
+	runner.run_repl_file(os.cachedir(), session.options.vexec, 'vlib/compiler/tests/repl/nothing.repl') or {
+		panic(err)
+	}
+
+	session.bmark.set_total_expected_steps( session.options.files.len )
+	mut ncpus := runtime.nr_cpus()
+	$if windows {
+	// See: https://docs.microsoft.com/en-us/cpp/build/reference/fs-force-synchronous-pdb-writes?view=vs-2019
+		ncpus = 1
+	}
+	session.waitgroup.add( ncpus )
+	for i:=0; i < ncpus; i++ {
+		go process_in_thread(session)
+	}
+	session.waitgroup.wait()
+	session.bmark.stop()
+	println(session.bmark.total_message('total time spent running REPL files'))
+}
+
+fn process_in_thread( session mut Session ){
+	cdir := os.cachedir()
+	mut tls_bench := benchmark.new_benchmark()
+	tls_bench.set_total_expected_steps( session.bmark.nexpected_steps )
+	for {
+		session.ntask_mtx.lock()
+		session.ntask++
+		idx := session.ntask-1
+		session.ntask_mtx.unlock()
+		
+		if idx >= session.options.files.len { break }
+		tls_bench.cstep = idx
+
+		tfolder := filepath.join( cdir, 'vrepl_tests_$idx')
+		if os.is_dir( tfolder ) {
+			os.rmdir_recursive( tfolder )
+		}
+		os.mkdir( tfolder ) or { panic(err) }
+		
+		file := os.realpath( filepath.join( session.options.wd, session.options.files[ idx ] ) )
+		session.bmark.step()
+		tls_bench.step()
+		fres := runner.run_repl_file(tfolder, session.options.vexec, file) or {
+			session.bmark.fail()
+			tls_bench.fail()
+			os.rmdir_recursive( tfolder )
+			eprintln(tls_bench.step_message_fail(err))
 			assert false
 			continue
 		}
-		bmark.ok()
-		println(bmark.step_message_ok(fres))
+		session.bmark.ok()
+		tls_bench.ok()
+		os.rmdir_recursive( tfolder )
+		println(tls_bench.step_message_ok(fres))
 		assert true
 	}
-	bmark.stop()
-	println(bmark.total_message('total time spent running REPL files'))
+	session.waitgroup.done()
 }
diff --git a/vlib/compiler/tests/repl/runner/runner.v b/vlib/compiler/tests/repl/runner/runner.v
index f7b3be59fa..7962a7d9c4 100644
--- a/vlib/compiler/tests/repl/runner/runner.v
+++ b/vlib/compiler/tests/repl/runner/runner.v
@@ -5,7 +5,7 @@ import (
 	filepath
 )
 
-struct RunnerOptions {
+pub struct RunnerOptions {
 pub:
 	wd string
 	vexec string
@@ -22,12 +22,12 @@ pub fn full_path_to_v(dirs_in int) string {
 	for i := 0; i < dirs_in; i++ {
 		path = filepath.dir(path)
 	}
-	vexec := path + os.path_separator + vname
+	vexec := filepath.join( path, vname )
 	/*
 	args := os.args
 	vreal  := os.realpath('v')
 	myself := os.realpath( os.executable() )
-	wd := os.getwd() + os.path_separator
+	wd := os.getwd()
 	println('args are: $args')
 	println('vreal   : $vreal')
 	println('myself  : $myself')
@@ -55,17 +55,24 @@ pub fn run_repl_file(wd string, vexec string, file string) ?string {
 	content := fcontent.replace('\r', '')		
 	input := content.all_before('===output===\n')
 	output := content.all_after('===output===\n')
-	
-	input_temporary_filename := 'input_temporary_filename.txt'
+
+	fname := filepath.filename( file )
+	input_temporary_filename := os.realpath(filepath.join( wd, 'input_temporary_filename.txt'))
 	os.write_file(input_temporary_filename, input)
-	rcmd := '"$vexec" repl < $input_temporary_filename'
+	os.write_file(  os.realpath(filepath.join( wd, 'original.txt' ) ), fcontent )
+	rcmd := '"$vexec" repl -replfolder "$wd" -replprefix "${fname}." < $input_temporary_filename'
 	r := os.exec(rcmd) or {
 		os.rm(input_temporary_filename)
 		return error('Could not execute: $rcmd')
 	}
 	os.rm(input_temporary_filename)
-
-	result := r.output.replace('\r','').replace('>>> ', '').replace('>>>', '').replace('... ', '').all_after('Use Ctrl-C or `exit` to exit\n').replace(wd, '' )
+	
+	result := r.output.replace('\r','')
+	.replace('>>> ', '')
+	.replace('>>>', '')
+	.replace('... ', '')
+	.all_after('Use Ctrl-C or `exit` to exit\n')
+	.replace(wd  + os.path_separator, '' )
 
 	if result != output {
 		file_result   := '${file}.result.txt'
@@ -120,7 +127,7 @@ $diff
 }
 
 pub fn new_options() RunnerOptions {
-	wd := os.getwd() + os.path_separator
+	wd := os.getwd()
 	vexec := full_path_to_v(5)
 	mut files := []string
 	if os.args.len > 1 {
@@ -136,7 +143,7 @@ pub fn new_options() RunnerOptions {
 }
 
 pub fn new_prod_options() RunnerOptions {
-	wd := os.getwd() + os.path_separator
+	wd := os.getwd()
 	vexec := full_path_to_v(4)
 	mut files := []string
 	if os.args.len > 1 {
diff --git a/vlib/runtime/runtime_win.v b/vlib/runtime/runtime_windows.v
similarity index 100%
rename from vlib/runtime/runtime_win.v
rename to vlib/runtime/runtime_windows.v