ESP8266WebServer responds sluggy to some client after commit 83a8076db87b77de6a7b500c18b85057e38ed117 #5173

jjsuwa · 2018-09-27T02:55:23Z

Example:
HTTP server (esp8266/Arduino simple HTTP server w/mDNS):

#include <ESP8266WiFi.h>
#include <ESP8266mDNS.h>
#include <ESP8266WebServer.h>

#define WIFI_SSID     "YOUR-WIFI-SSID"
#define WIFI_PASSWORD "YOUR-WIFI-PASSWORD"
#define MDNS_HOSTNAME "avahi"

static ESP8266WebServer webServer(80);

void setup() {
  Serial.begin(115200);
  delay(250);
  Serial.print(F("\n\nconnecting to WiFi"));
  WiFi.persistent(false);
  // WiFiClient::setDefaultNoDelay(false);
  // WiFiClient::setDefaultSync(false);
  WiFi.mode(WIFI_STA);
  WiFi.begin(String(F(WIFI_SSID)).c_str(), String(F(WIFI_PASSWORD)).c_str());
  for (; ; delay(500)) {
    if (WiFi.status() == WL_CONNECTED)
      break;
    Serial.print('.');
  }
  Serial.print(F(", done.\n"));  MDNS.begin(String(F(MDNS_HOSTNAME)).c_str());
  MDNS.addService(F("http"), F("tcp"), 80);
  webServer.onNotFound([]() {
    webServer.send(404);
  });
  webServer.on(F("/"), HTTP_GET, []() {
    webServer.sendHeader(F("Location"), String(F("http://" MDNS_HOSTNAME ".local/index.html")));
    webServer.send(302);
  });
  webServer.on(F("/index.html"), HTTP_GET, []() {
    webServer.send(200, F("text/html"), F("<!DOCTYPE html><html>"
                                          "<head><meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\"/><title>WiFi HTTP server test</title></head>"
                                          "<body><h1>WiFi HTTP server test</h1><p>hello world</p></body>"
                                          "</html>"));
  });
  webServer.begin();
}

void loop() {
  webServer.handleClient();
}

and 2 equivalent HTTP clients... (C# Windows 7/ndp20):

using System;
using System.Diagnostics;
using System.IO;
using System.Net;

namespace httprequest2avahi
{
    internal static class Program
    {
        public static void Main(String[] args)
        {
            String url = String.Format("http://{0}/index.html", Dns.GetHostAddresses("avahi.local")[0]);
            Stopwatch sw = new Stopwatch();
            for(Int32 i = 1; ; ++i)
            {
                HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
                req.Timeout = 60000;
                req.ReadWriteTimeout = 60000;
                req.KeepAlive = false;
                req.Pipelined = false;
                sw.Reset();
                sw.Start();
                using(HttpWebResponse res = (HttpWebResponse)req.GetResponse())
                {
                    sw.Stop();
                    Double d = sw.Elapsed.TotalSeconds;
                    if(d > 1)
                        Console.WriteLine("[{0}] req.GetResponse(): {1} seconds", DateTime.Now, d);
                    if(res.StatusCode != HttpStatusCode.OK)
                        break;
                    using(Stream s = res.GetResponseStream())
                    using(StreamReader sr = new StreamReader(s))
                        sr.ReadToEnd();
                }
                Console.Write("connected {0} times\r", i);
            }
        }
    }
}

(Python3 Windows 7 or Raspberry Pi 3B):

#!/usr/bin/env python3

import http.client
import itertools
import socket
from datetime import datetime

if __name__ == "__main__":
    conn = http.client.HTTPConnection(socket.gethostbyname("avahi.local"), 80, timeout=60)
    for i in itertools.count(1):
        t = datetime.now()
        conn.request("GET", "/index.html")
        d = (datetime.now() - t).total_seconds()
        if d > 1:
            print(" [{}] conn.request(): {} seconds\n".format(t, d))
        with conn.getresponse() as res:
            if res.status != 200:
                break
            res.read()
        print("connected {} times\r".format(i), end="")

On commit 88bd26b (or earlier),

both 2 abovementioned clients receive responses well (100+ per second)

However on commit 83a8076 ~ 7c91eee,

C# client receives suddenly slow (2~3 per second), but Pythons well
WiFiClient::setDefaultNoDelay(true) recovers the performance

Moreover on commit 775eb9b,

C# client performance degradation like the above
WiFiClient::setDefaultNoDelay(true) is ineffective now

Additional Info:
Patched with

   });
   webServer.on(F("/index.html"), HTTP_GET, []() {
-    webServer.send(200, F("text/html"), F("<!DOCTYPE html><html>"
-                                          "<head><meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\"/><title>WiFi HTTP server test</title></head>"
-                                          "<body><h1>WiFi HTTP server test</h1><p>hello world</p></body>"
-                                          "</html>"));
+#define BLOB_SIZE 3996
+    static const char blob[BLOB_SIZE] PROGMEM = { 0 };
+    webServer.send_P(200, PSTR("application/octet-stream"), blob, BLOB_SIZE);
   });
   webServer.begin();

and then,

#define BLOB_SIZE 3996 is OK but 3995 isn't. Related to MSS or # of packet? (lwIP Variant: "v2 Low Memory")

The text was updated successfully, but these errors were encountered:

d-a-v · 2018-09-27T07:45:28Z

I will not be able to easily run C#,
can you try this in libraries/ESP8266WiFi/src/include/ClientContext.h L493:
change
uint8_t flags = TCP_WRITE_FLAG_MORE; // do not tcp-PuSH
to
uint8_t flags = 0; // TCP_WRITE_FLAG_MORE; // do not tcp-PuSH

jjsuwa · 2018-09-27T08:15:45Z

@d-a-v - can you try this ~

Bingo! It recovers C# client performance w/o setDefaultNoDelay(true), and python one also works well :)

d-a-v · 2018-09-27T08:58:16Z

Thanks !
Let me some time to try to set the PuSH flag only in the last write, as stated in this interesting explanation.

edit: that, because I suspect this flag to break Nagle, I need to check again
edit2: we've been here before: #1577

d-a-v · 2018-09-27T13:34:19Z

Can you please retry with C# and this:

            uint8_t flags = 0;
            if (next_chunk_size < _datasource->available())
                flags |= TCP_WRITE_FLAG_MORE; // do not tcp-PuSH

fix esp8266#5173

jjsuwa · 2018-09-27T14:06:13Z

@d-a-v - Can you please retry with C# and this

LGTM.

fix #5173

devyte assigned d-a-v Sep 27, 2018

d-a-v added a commit to d-a-v/Arduino that referenced this issue Sep 27, 2018

ClientContext: restore TCP PuSH flasg when needed

2e9bda8

fix esp8266#5173

d-a-v mentioned this issue Sep 27, 2018

ClientContext: restore TCP PuSH flag when needed #5176

Merged

d-a-v closed this as completed in #5176 Sep 27, 2018

d-a-v added a commit that referenced this issue Sep 27, 2018

ClientContext: restore TCP PuSH flasg when needed (#5176)

5a5af55

fix #5173

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ESP8266WebServer responds sluggy to some client after commit 83a8076db87b77de6a7b500c18b85057e38ed117 #5173

ESP8266WebServer responds sluggy to some client after commit 83a8076db87b77de6a7b500c18b85057e38ed117 #5173

jjsuwa commented Sep 27, 2018 •

edited

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d-a-v commented Sep 27, 2018 •

edited

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jjsuwa commented Sep 27, 2018

d-a-v commented Sep 27, 2018 •

edited

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d-a-v commented Sep 27, 2018

jjsuwa commented Sep 27, 2018

ESP8266WebServer responds sluggy to some client after commit 83a8076db87b77de6a7b500c18b85057e38ed117 #5173

ESP8266WebServer responds sluggy to some client after commit 83a8076db87b77de6a7b500c18b85057e38ed117 #5173

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jjsuwa commented Sep 27, 2018 • edited Loading

d-a-v commented Sep 27, 2018 • edited Loading

jjsuwa commented Sep 27, 2018

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d-a-v commented Sep 27, 2018

jjsuwa commented Sep 27, 2018

jjsuwa commented Sep 27, 2018 •

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d-a-v commented Sep 27, 2018 •

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d-a-v commented Sep 27, 2018 •

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