From d656d136098f779724cec5aa23a36fac5d72a7d2 Mon Sep 17 00:00:00 2001
From: Francesc Alted <francesc@blosc.org>
Date: Tue, 14 Jan 2025 11:51:46 +0100
Subject: [PATCH] Some fine tuning on the number of threads

---
 src/blosc2/__init__.py | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/blosc2/__init__.py b/src/blosc2/__init__.py
index 760eaf97..4a985a1c 100644
--- a/src/blosc2/__init__.py
+++ b/src/blosc2/__init__.py
@@ -12,6 +12,8 @@
 
 from enum import Enum
 
+import numexpr
+
 from .version import __version__
 
 __version__ = __version__
@@ -195,7 +197,9 @@ class Tuner(Enum):
 # Protection against too many threads
 nthreads = min(nthreads, 32)
 # Experiments say that, when using a large number of threads, it is better to not use them all
-nthreads -= nthreads // 8
+if nthreads > 16:
+    nthreads -= nthreads // 8
+numexpr.set_num_threads(nthreads)
 
 # This import must be before ndarray and schunk
 from .storage import (  # noqa: I001