From 465b4d89a48ce758f8f151af6e2b922985ef117d Mon Sep 17 00:00:00 2001
From: Stephan Hageboeck <stephan.hageboeck@cern.ch>
Date: Thu, 26 Jun 2025 15:53:33 +0200
Subject: [PATCH] Add info about ROOT_MAX_THREADS to manual.

---
 manual/multi_threading/index.md | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/manual/multi_threading/index.md b/manual/multi_threading/index.md
index 0794bba7..d03838b3 100644
--- a/manual/multi_threading/index.md
+++ b/manual/multi_threading/index.md
@@ -39,6 +39,12 @@ h = rdf.Filter("x > 0").Histo1D("x")
 h.Draw()
 {% endhighlight %}
 
+There are two options to limit the number of threads ROOT is going to use: using `ROOT::EnableImplicitMT(4)` or setting the environment variable ROOT_MAX_THREADS, for example:
+{% highlight Bash %}
+export ROOT_MAX_THREADS=4
+root.exe ${arguments}
+{% endhighlight %}
+
 For further information about RDataFrame, please visit → [RDataFrame manual]({{ '/manual/data_frame' | relative_url }}).
 
 In addition to RDataFrame, the methods and classes below also implement IMT in ROOT: