Slow WiFiClient after commit "ClientContext (tcp) updates #5089" #5170
Description
Hi!
I realized that after the last commit (ClientContext (tcp) updates (#5089)), my Webserver was very slow while sending big files.
I looked at the changes and it seems that ClientContext::_write_some() causes the problem.
My suspicion is, that the if-condition in line 510 should be reverted so that tcp_output is always called.
If I set WiFiClient::setDefaultNoDelay(true) at the beginning of my program, it works.
Possible solution:
ClientContext::_write_some (line 510):
Change
if (has_written && (_sync || tcp_nagle_disabled(_pcb))) {
...
tcp_output(_pcb);
}
to
if (has_written) {
...
tcp_output(_pcb);
}
Testcode:
Compile and visit IP address in webbrowser.
Toggle variable NO_DELAY to see effect.
#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <ESP8266WebServer.h>
const char* ssid = "***";
const char* password = "***";
constexpr size_t HUGE_PAGE_SIZE = 32 * 1024;
constexpr bool NO_DELAY = false;
ESP8266WebServer server(80);
void setup(void) {
WiFiClient::setDefaultNoDelay(NO_DELAY);
Serial.begin(115200);
WiFi.mode(WIFI_STA);
WiFi.begin(ssid, password);
Serial.println("");
// Wait for connection
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.print("Connected to ");
Serial.println(ssid);
Serial.print("IP address: ");
Serial.println(WiFi.localIP());
server.onNotFound([]() {
const String html = "<html><header><title>A test</title></header><body>A huge page</body></html>";
String hugePage;
hugePage.reserve(HUGE_PAGE_SIZE+html.length());
for (size_t i = 0; i != HUGE_PAGE_SIZE; ++i) {
hugePage += ' ';
}
hugePage += html;
Serial.print("Sending huge page ");
Serial.print(NO_DELAY?"WITHOUT": "WITH");
Serial.print(" Nagle Algorithm...");
ulong t1 = millis();
server.send(200, "text/html", hugePage);
ulong t2 = millis();
Serial.print("done. Time: ");
Serial.print(t2-t1);
Serial.println("ms");
});
server.begin();
Serial.println("HTTP server started");
}
void loop(void) {
server.handleClient();
}Debug Messages
Sending huge page WITH Nagle Algorithm...done. Time: 15542ms
Sending huge page WITHOUT Nagle Algorithm...done. Time: 318ms
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