From 4c3f289c1977b05e6d8e784a804b9f5319c3ec2d Mon Sep 17 00:00:00 2001
From: Tom Mrazauskas <tom@mrazauskas.de>
Date: Sat, 27 Jul 2024 13:05:17 +0300
Subject: [PATCH] fix: always use half of available parallelism (#611)

* fix: always use half of available parallelism

* fix fallback docs

* revert docs

* tweak logic
---
 src/polyfills/cpus.ts                                   | 4 ++--
 src/services/run-tests.ts                               | 3 ++-
 website/docs/documentation/poku/options/concurrency.mdx | 3 ++-
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/polyfills/cpus.ts b/src/polyfills/cpus.ts
index 633ee74e..d1bf05ee 100644
--- a/src/polyfills/cpus.ts
+++ b/src/polyfills/cpus.ts
@@ -5,5 +5,5 @@ import {
 
 export const availableParallelism = (): number =>
   typeof nodeAvailableParallelism === 'function'
-    ? Math.floor(nodeAvailableParallelism() / 2)
-    : (cpus()?.length ?? 1);
+    ? nodeAvailableParallelism()
+    : (cpus()?.length ?? 0);
diff --git a/src/services/run-tests.ts b/src/services/run-tests.ts
index 27138846..03568042 100644
--- a/src/services/run-tests.ts
+++ b/src/services/run-tests.ts
@@ -97,7 +97,8 @@ export const runTestsParallel = async (
     ? [sanitizePath(dir)]
     : await listFiles(testDir, configs);
   const filesByConcurrency: string[][] = [];
-  const concurrencyLimit = configs?.concurrency ?? availableParallelism();
+  const concurrencyLimit =
+    configs?.concurrency ?? Math.max(Math.floor(availableParallelism() / 2), 1);
   const concurrencyResults: (boolean | undefined)[][] = [];
   const showLogs = !isQuiet(configs);
 
diff --git a/website/docs/documentation/poku/options/concurrency.mdx b/website/docs/documentation/poku/options/concurrency.mdx
index 252a70b5..e24cfb78 100644
--- a/website/docs/documentation/poku/options/concurrency.mdx
+++ b/website/docs/documentation/poku/options/concurrency.mdx
@@ -5,7 +5,8 @@ sidebar_position: 8
 # `concurrency`
 
 When using `parallel` option, use `concurrency` to limit the number of tests running concurrently.<br />
-The default value is `0` (no limit).
+The default value is half of the available cores. When available, the `os.availableParallelism()` method is used. Otherwise Poku looks at the `os.cpus().length` or sets the value to `1`.<br />
+To allow unlimited parallelism set the value to `0`.
 
 ## CLI