ArduinoJson measure deserialization speed

DeserializeFromRam.ino

// https://github.com/bblanchon/ArduinoJson/issues/1593

#include <ArduinoJson.h>

void setup() {
  // Initialize serial port
  Serial.begin(115200);
  while (!Serial) continue;

}

void loop() {
  StaticJsonDocument<1024> doc;
  char json[] = "{\"sensor\":\"gps\",\"time\":1351824120,\"data\":[48.756080,2.302038]}";

  unsigned long start = micros();
  deserializeJson(doc, json);
  unsigned long stop = micros();
  Serial.println(stop - start);  // about 640µs on UNO

  delay(1000);
}

DeserializeFromSerial.ino

// https://github.com/bblanchon/ArduinoJson/issues/1593

#include <ArduinoJson.h>

void setup() {
  // Initialize serial port
  Serial.begin(115200);
  while (!Serial) continue;

}

void loop() {
  if (!Serial.available()) return;
    
  StaticJsonDocument<1024> doc;
  
  unsigned long start = micros();
  DeserializationError err = deserializeJson(doc, Serial);
  unsigned long stop = micros();  // about 1280µs

  Serial.println(err.c_str());
  Serial.println(stop - start);
}