diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index bd173e228e17a474ba98d560d3465242a8989134..7a92c5b89f5cdf0710f06bf6979a86db89adcfc6 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -4,7 +4,7 @@ stages:
   - build
 
 variables:
-  CPU_CORES: "9"
+  CPU_CORES: "10"
 
 .template: &template
   stage: build
@@ -18,6 +18,8 @@ variables:
   - 'time make -k -j$CPU_CORES TIMED=y 2>&1 | tee build-log.txt'
   - 'if fgrep Axiom build-log.txt >/dev/null; then exit 1; fi'
   - 'cat build-log.txt | egrep "[a-zA-Z0-9_/-]+ \((real|user): [0-9]" | tee build-time.txt'
+  # maybe validate
+  - 'if [[ -n "$VALIDATE" ]]; then make validate; fi'
   # maybe generate and upload doc (has to be in this job as we need coq installed)
   - 'if [[ -n "$DOCDIR" && "$CI_COMMIT_REF_NAME" == master ]]; then build/coqdoc; fi'
   # maybe create opam package
diff --git a/build/opam-ci.sh b/build/opam-ci.sh
index b6925ba58c8518c2f6a73ad74833861073ff9578..bc51df87ef1e4c3867512df9f8b309111109a151 100755
--- a/build/opam-ci.sh
+++ b/build/opam-ci.sh
@@ -63,5 +63,6 @@ echo "[opam-ci] Installing build-dependencies"
 make build-dep OPAMFLAGS=-y
 
 # done
+set +x
 echo
 coqc -v