From 319fd1d0173850638eed2bd80682848863458e0a Mon Sep 17 00:00:00 2001
From: Martin Kroeker <martin@ruby.chemie.uni-freiburg.de>
Date: Mon, 28 Jun 2021 18:51:47 +0200
Subject: [PATCH] Add multithreading threshold

---
 interface/lapack/getrf.c  | 9 ++++++++-
 interface/lapack/zgetrf.c | 5 ++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/interface/lapack/getrf.c b/interface/lapack/getrf.c
index 02bb124b3..323370ebc 100644
--- a/interface/lapack/getrf.c
+++ b/interface/lapack/getrf.c
@@ -95,7 +95,14 @@ int NAME(blasint *M, blasint *N, FLOAT *a, blasint *ldA, blasint *ipiv, blasint
 
 #ifdef SMP
   args.common = NULL;
-  args.nthreads = num_cpu_avail(4);
+#ifndef DOUBLE
+  if (args.m*args.n < 40000)
+#else
+  if (args.m*args.n < 10000)
+#endif
+	args.nthreads=1;
+  else
+	args.nthreads = num_cpu_avail(4);
 
   if (args.nthreads == 1) {
 #endif
diff --git a/interface/lapack/zgetrf.c b/interface/lapack/zgetrf.c
index 7f8db94f6..d03541fad 100644
--- a/interface/lapack/zgetrf.c
+++ b/interface/lapack/zgetrf.c
@@ -95,7 +95,10 @@ int NAME(blasint *M, blasint *N, FLOAT *a, blasint *ldA, blasint *ipiv, blasint
 
 #ifdef SMP
   args.common = NULL;
-  args.nthreads = num_cpu_avail(4);
+  if (args.m*args.n <10000)
+	args.nthreads = 1;
+  else
+	args.nthreads = num_cpu_avail(4);
 
   if (args.nthreads == 1) {
 #endif