diff --git a/python-chardet.spec b/python-chardet.spec
index a84cad8..cdddd3e 100644
--- a/python-chardet.spec
+++ b/python-chardet.spec
@@ -94,7 +94,8 @@ echo "latex_engine = 'xelatex'" >> docs/conf.py
 %pyproject_wheel
 
 %if %{with doc_pdf}
-PYTHONPATH="${PWD}" %make_build -C docs latex SPHINXOPTS='%{?_smp_mflags}'
+PYTHONPATH="${PWD}" %make_build -C docs latex \
+    SPHINXOPTS='-j%{?_smp_build_ncpus}'
 %make_build -C docs/_build/latex LATEXMKOPTS='-quiet'
 %endif