SPIFFS into esp32 flashram: Reading is 8 times slower than writing a file ?

[euquiq]

I am using latest ESP32 Arduino framework.

I always thought reading a file should be really faster than writing. But I already tested it in several ESP32 boards I got in here and I am getting just the opposite result.

This is the code I am using:

#include "FS.h"
#include "SPIFFS.h"

void setup()
{
	Serial.begin(115200);
	delay(1000);
	ulong ini, fin = 0;
	if (!SPIFFS.begin(true)) {
		Serial.println("SPIFFS Mount Failed");
	}
	else
	{
		//
		// FORMAT
		//
		Serial.print("FORMAT: ");
		ini = millis();
		SPIFFS.format();
		fin = millis();
		fin = fin - ini;
		Serial.println((String)fin + " millis");
		String filename = "/test";
		//
		// CREATE FILE AND PUT SOME TEXT
		//
		Serial.print("CREATE / WRITE: ");
		ini = millis();
		File file = SPIFFS.open(filename, FILE_WRITE);
		file.println("EXAMPLE TEXT CONTENT");
		file.flush();
		file.close();
		fin = millis();
		fin = fin - ini;
		Serial.println((String)fin + " millis");
		//
		// READ FILE
		//
		Serial.print("READ: ");
		String result = "";
		ini = millis();
		File file2 = SPIFFS.open(filename);
		result = file2.readString();
		fin = millis();
		fin = fin - ini;
		Serial.println((String)fin + " millis / result: " + result);
	}
}

void loop()
{
	delay(5000);
}

This is the Output I am getting:

FORMAT: 14508 millis
CREATE / WRITE: 156 millis
READ: 1001 millis / result: EXAMPLE TEXT CONTENT

I am assuming I am doing something (VERY) wrong, but just in case, I am anyway raising an issue!

Regards,

Enrique

[me-no-dev]

Fixed :) readString was waiting for timeout (Stream function)