diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 28e8e1605e256cf0c6776675734ca7c4500454c3..c922ec2914b670c23662765f6ba5154b1d054bda 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -7,7 +7,10 @@ iris-coq8.6:
   # prepare
   - . build/opam-ci.sh coq 8.6 coq-mathcomp-ssreflect 1.6.1
   # build
-  - 'time make -j8'
+ - 'time make -j8 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_/-]+ \(user: [0-9]" | tee build-time.txt'
+ - 'if (( RANDOM % 10 == 0 )); then make validate; fi'
   cache:
     key: "coq8.6"
     paths: