--- CV/CV.xs	2021/11/28 23:26:51	1.63
+++ CV/CV.xs	2021/12/02 03:11:45	1.65
@@ -591,11 +591,18 @@
         size_t avail_in = SvCUR (image_data);
         const char *error = 0;
         JxlDecoderStatus status;
+        static void *runner_cache;
         void *runner = 0;
-        struct bmff_box box;
 
         RETVAL = 0;
 
+        if (runner_cache)
+          runner = runner_cache;
+        else
+          runner = JxlThreadParallelRunnerCreate (0, JxlThreadParallelRunnerDefaultNumWorkerThreads ());
+
+        runner_cache = 0;
+
         perlinterp_release ();
 
         dec = JxlDecoderCreate (0);
@@ -604,8 +611,6 @@
         if (!dec)
           goto done;
 
-        runner = JxlThreadParallelRunnerCreate (0, JxlThreadParallelRunnerDefaultNumWorkerThreads ());
-
         status = JxlDecoderSetParallelRunner (dec, JxlThreadParallelRunner, runner);
         error = "JxlDecoderSetParallelRunner failed";
         if (status != JXL_DEC_SUCCESS)
@@ -690,10 +695,12 @@
         if (dec)
 	  JxlDecoderDestroy (dec);
 
-        if (runner)
+        perlinterp_acquire ();
+
+        if (runner_cache)
           JxlThreadParallelRunnerDestroy (runner);
 
-        perlinterp_acquire ();
+        runner_cache = runner;
 
         if (error)
           {