diff --git a/docker/test/performance-comparison/compare.sh b/docker/test/performance-comparison/compare.sh
index 593be2e630c..56398548756 100755
--- a/docker/test/performance-comparison/compare.sh
+++ b/docker/test/performance-comparison/compare.sh
@@ -1242,8 +1242,8 @@ create table ci_checks engine File(TSVWithNamesAndTypes, 'ci-checks.tsv')
         'Performance' check_name,
         '$(sed -n 's/.*<!--status: \(.*\)-->/\1/p' report.html)' check_status,
         -- TODO toDateTime() can't parse output of 'date', so no time for now.
-        3600 * 1000 check_duration_ms,
-        now() - check_duration_ms / 1000 check_start_time,
+        ($(date +%s) - $CHPC_CHECK_START_TIMESTAMP) * 1000 check_duration_ms,
+        fromUnixTimestamp($CHPC_CHECK_START_TIMESTAMP) check_start_time,
         test_name,
         test_status,
         test_duration_ms,
diff --git a/docker/test/performance-comparison/entrypoint.sh b/docker/test/performance-comparison/entrypoint.sh
index 570a1c21514..ffa79080260 100755
--- a/docker/test/performance-comparison/entrypoint.sh
+++ b/docker/test/performance-comparison/entrypoint.sh
@@ -1,6 +1,8 @@
 #!/bin/bash
 set -ex
 
+export CHPC_CHECK_START_TIMESTAMP="$(date +%s)"
+
 # Use the packaged repository to find the revision we will compare to.
 function find_reference_sha
 {