diff --git a/components/esp_hw_support/sleep_modes.c b/components/esp_hw_support/sleep_modes.c
index e6b02e1d22..21bc951e6b 100644
--- a/components/esp_hw_support/sleep_modes.c
+++ b/components/esp_hw_support/sleep_modes.c
@@ -1639,7 +1639,13 @@ static uint32_t get_power_down_flags(void)
     return pd_flags;
 }
 
-void esp_deep_sleep_disable_rom_logging(void)
+#if CONFIG_IDF_TARGET_ESP32
+/* APP core of esp32 can't access to RTC FAST MEMORY, do not define it with RTC_IRAM_ATTR */
+void
+#else
+void RTC_IRAM_ATTR
+#endif
+esp_deep_sleep_disable_rom_logging(void)
 {
     rtc_suppress_rom_log();
 }
diff --git a/examples/system/deep_sleep_wake_stub/main/rtc_wake_stub_example.c b/examples/system/deep_sleep_wake_stub/main/rtc_wake_stub_example.c
index 628af418c1..acb871d846 100644
--- a/examples/system/deep_sleep_wake_stub/main/rtc_wake_stub_example.c
+++ b/examples/system/deep_sleep_wake_stub/main/rtc_wake_stub_example.c
@@ -6,6 +6,8 @@
 
 #include <inttypes.h>
 #include "esp_sleep.h"
+#include "esp_cpu.h"
+#include "esp_rom_sys.h"
 #include "esp_wake_stub.h"
 #include "sdkconfig.h"
 
@@ -33,15 +35,20 @@ static const uint32_t s_max_count = 20;
 // wakeup_cause stored in RTC memory
 static uint32_t wakeup_cause;
 
+// wakeup_time from CPU start to wake stub
+static uint32_t wakeup_time;
+
 // wake up stub function stored in RTC memory
 void wake_stub_example(void)
 {
+    // Get wakeup time.
+    wakeup_time = esp_cpu_get_cycle_count() / esp_rom_get_cpu_ticks_per_us();
     // Get wakeup cause.
     wakeup_cause = esp_wake_stub_get_wakeup_cause();
     // Increment the counter.
     s_count++;
     // Print the counter value and wakeup cause.
-    ESP_RTC_LOGI("wake stub: wakeup count is %d, wakeup cause is %d", s_count, wakeup_cause);
+    ESP_RTC_LOGI("wake stub: wakeup count is %d, wakeup cause is %d, wakeup cost %ld us", s_count, wakeup_cause, wakeup_time);
 
     if (s_count >= s_max_count) {
         // Reset s_count