diff --git a/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/optimizer/run.rkt b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/optimizer/run.rkt
index 23a1a1b61d..3c70bd2a9f 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/optimizer/run.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/optimizer/run.rkt
@@ -8,19 +8,22 @@
          test-opt test-missed-optimization test-file?
          generate-log tests-dir missed-optimizations-dir)
 
+(define (get-expected-results file)
+  (with-input-from-file file
+    (lambda () ; from the test file
+      (read-line) ; skip the #;#;
+      (values (for/list ((l (in-lines (open-input-string (read))))) l)
+              (read)))))
+
 ;; we log optimizations and compare to an expected log to make sure that all
 ;; the optimizations we expected did indeed happen
-(define (compare-logs name dir)
+(define (compare-logs name dir promised-logs)
   (test-suite
     (format "Log Comparison for ~a" name)
     (test-begin
-      (define-values (log output) (generate-log name dir))
+      (define-values (log output) (force promised-logs))
       (define-values (expected-log expected-output)
-        (with-input-from-file (build-path dir name)
-          (lambda () ; from the test file
-            (read-line) ; skip the #;#;
-            (values (for/list ((l (in-lines (open-input-string (read))))) l)
-                    (read)))))
+        (get-expected-results (build-path dir name)))
 
       (check-equal? log expected-log)
       (check-equal? output expected-output))))
@@ -30,10 +33,10 @@
 (define-runtime-path missed-optimizations-dir "./missed-optimizations")
 
 ;; these two return lists of tests to be run for that category of tests
-(define (test-opt name)
-  (compare-logs name tests-dir))
-(define (test-missed-optimization name)
-  (compare-logs name missed-optimizations-dir))
+(define (test-opt name logs)
+  (compare-logs name tests-dir logs))
+(define (test-missed-optimization name logs)
+  (compare-logs name missed-optimizations-dir logs))
 
 (define (test-file? name)
   (and (regexp-match ".*rkt$" name)
@@ -42,11 +45,13 @@
 
 ;; proc returns the list of tests to be run on each file
 (define (mk-suite suite-name dir proc)
-  (make-test-suite
-    suite-name
-    (for/list ([name (directory-list dir)]
-               #:when (test-file? name))
-      (proc name))))
+  (test-suite suite-name
+    (let* ((logs (for/hash ([name (directory-list dir)]
+                            #:when (test-file? name))
+                   (values name (delay/thread (generate-log name dir))))))
+      (make-test-suite ""
+        (for/list (((name logs) logs))
+          (proc name logs))))))
 
 (define (optimization-tests)
   (mk-suite "Optimization Tests" tests-dir test-opt))