diff --git a/cores/esp32/Esp.cpp b/cores/esp32/Esp.cpp
index 8df9514ee66..54451127ef3 100644
--- a/cores/esp32/Esp.cpp
+++ b/cores/esp32/Esp.cpp
@@ -92,13 +92,6 @@ void EspClass::deepSleep(uint32_t time_us)
     esp_deep_sleep(time_us);
 }
 
-uint32_t EspClass::getCycleCount()
-{
-    uint32_t ccount;
-    __asm__ __volatile__("esync; rsr %0,ccount":"=a" (ccount));
-    return ccount;
-}
-
 void EspClass::restart(void)
 {
     esp_restart();
diff --git a/cores/esp32/Esp.h b/cores/esp32/Esp.h
index 9acb6665c3d..2580eecf65b 100644
--- a/cores/esp32/Esp.h
+++ b/cores/esp32/Esp.h
@@ -76,7 +76,7 @@ class EspClass
 
     uint8_t getChipRevision();
     uint32_t getCpuFreqMHz(){ return getCpuFrequencyMhz(); }
-    uint32_t getCycleCount();
+    inline uint32_t getCycleCount() __attribute__((always_inline));
     const char * getSdkVersion();
 
     void deepSleep(uint32_t time_us);
@@ -101,6 +101,13 @@ class EspClass
 
 };
 
+uint32_t IRAM_ATTR EspClass::getCycleCount()
+{
+    uint32_t ccount;
+    __asm__ __volatile__("esync; rsr %0,ccount":"=a" (ccount));
+    return ccount;
+}
+
 extern EspClass ESP;
 
 #endif //ESP_H