diff --git a/runtime/include/local_runqueue.h b/runtime/include/local_runqueue.h
index 40bf0b2..5a267d2 100644
--- a/runtime/include/local_runqueue.h
+++ b/runtime/include/local_runqueue.h
@@ -4,6 +4,8 @@
 
 #include "sandbox_types.h"
 
+
+#define TEST_RECORDING_BUFFER_LEN       500000
 /* Returns pointer back if successful, null otherwise */
 typedef void (*local_runqueue_add_fn_t)(struct sandbox *);
 typedef bool (*local_runqueue_is_empty_fn_t)(void);
diff --git a/runtime/src/main.c b/runtime/src/main.c
index 46858f4..c92319c 100644
--- a/runtime/src/main.c
+++ b/runtime/src/main.c
@@ -356,7 +356,7 @@ main(int argc, char **argv)
 	char *cpu_speed_MHz_raw = getenv("SLEDGE_CPU_SPEED");
 	if (cpu_speed_MHz_raw != NULL) {
                 long cpu_speed_MHz = atoi(cpu_speed_MHz_raw);
-                if (unlikely(cpu_speed_MHz < 0)) panic("SLEDGE_CPU_SPEED must be a positive integer, saw %ld\n", cpu_speed_MHz);
+                if (unlikely(cpu_speed_MHz <= 0)) panic("SLEDGE_CPU_SPEED must be a positive integer, saw %ld\n", cpu_speed_MHz);
                 runtime_processor_speed_MHz = (uint32_t)cpu_speed_MHz;
         }
         printf("\tCPU Speed: %u MHz\n", runtime_processor_speed_MHz);
diff --git a/runtime/src/software_interrupt.c b/runtime/src/software_interrupt.c
index 96072d6..b9a07b7 100644
--- a/runtime/src/software_interrupt.c
+++ b/runtime/src/software_interrupt.c
@@ -31,6 +31,9 @@ static uint64_t software_interrupt_interval_duration_in_cycles;
 /******************
  * Thread Globals *
  *****************/
+extern __thread uint32_t local_workload_count;
+extern __thread int recording_buffer[];
+extern __thread int worker_thread_idx;
 
 __thread _Atomic static volatile sig_atomic_t software_interrupt_SIGALRM_kernel_count = 0;
 __thread _Atomic static volatile sig_atomic_t software_interrupt_SIGALRM_thread_count = 0;
@@ -168,6 +171,9 @@ software_interrupt_handle_signals(int signal_type, siginfo_t *signal_info, void
 
 	switch (signal_type) {
 	case SIGALRM: {
+		assert(TEST_RECORDING_BUFFER_LEN > software_interrupt_SIGALRM_kernel_count + software_interrupt_SIGALRM_thread_count);
+		/* record queuelength of the current worker thread */
+		recording_buffer[software_interrupt_SIGALRM_kernel_count + software_interrupt_SIGALRM_thread_count] = local_workload_count;
 		sigalrm_propagate_workers(signal_info);
 		if (current_sandbox == NULL || current_sandbox->ctxt.preemptable == false) {
 			/* Cannot preempt, so defer signal
@@ -198,8 +204,15 @@ software_interrupt_handle_signals(int signal_type, siginfo_t *signal_info, void
 		goto done;
 	}
 	case SIGINT: {
+		/* Stop the alarm timer first */
+		software_interrupt_disarm_timer();
 		/* Only the thread that receives SIGINT from the kernel or user space will broadcast SIGINT to other worker threads */
 		sigint_propagate_workers_listener(signal_info);
+		mem_log("thread id %d test buffer:",worker_thread_idx);
+		for(int i = 0; i < software_interrupt_SIGALRM_kernel_count + software_interrupt_SIGALRM_thread_count; i++) {
+			mem_log("%d ", recording_buffer[i]);
+		}
+		mem_log("\n");
 		dump_log_to_file();
 		/* terminate itself */	
 		pthread_exit(0);	
diff --git a/runtime/src/worker_thread.c b/runtime/src/worker_thread.c
index 222624c..10e7e6b 100644
--- a/runtime/src/worker_thread.c
+++ b/runtime/src/worker_thread.c
@@ -21,6 +21,10 @@
  * Worker Thread State     *
  **************************/
 
+extern uint32_t test_recording_buffer_len;
+/* test recording buffer for saving queuelength */
+__thread int recording_buffer[TEST_RECORDING_BUFFER_LEN] = {0};
+ 
 /* context of the runtime thread before running sandboxes or to resume its "main". */
 __thread struct arch_context worker_thread_base_context;