Netty 4.1.19 http encode header cost too many time reach 10ms

Expected behavior

I use netty send http request ,find cost too much time ,I add log for the follower,found too many time is cost encode header part

Actual behavior

[28 18:33:59,778 INFO ] [ioNioEventLoopGroup-Southgate-1-15] http.HttpObjectEncoder - Finish encode request initial line … [28 18:33:59,789 INFO ] [ioNioEventLoopGroup-Southgate-1-15] http.HttpObjectEncoder - Finish encode request header …

cost time 789-778 = 11ms

Steps to reproduce

Minimal yet complete reproducer code (or URL to code)

public static void main(String[] args){

    HttpVersion httpVersion = HttpVersion.HTTP_1_0;
    HttpMethod method = HttpMethod.GET;
    ByteBuf buf = ByteBufAllocator.DEFAULT.buffer();
    ByteBuf content = Unpooled.EMPTY_BUFFER;
   // new DefaultFullHttpRequest(httpVersion,method, urlAddress,content);
    DefaultFullHttpRequest nettyHttpRequest = new DefaultFullHttpRequest(httpVersion,method,"http://localhost/aaa/bbb",content);
    //头里加入host信息
    nettyHttpRequest.headers().add(HttpHeaderNames.HOST, new AsciiString("192.168.3.52:8081"));
    nettyHttpRequest.headers().add(HttpHeaderNames.USER_AGENT, new AsciiString("Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:53.0) Gecko/20100101 Firefox/53.0"));
    nettyHttpRequest.headers().add(HttpHeaderNames.CONTENT_TYPE, new AsciiString("text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"));
    nettyHttpRequest.headers().add(HttpHeaderNames.ACCEPT_LANGUAGE, new AsciiString("zh-CN,zh;q=0.8,en-US;q=0.5,en;q=0.3"));
    nettyHttpRequest.headers().add(HttpHeaderNames.ACCEPT_ENCODING, new AsciiString("gzip, deflate"));
    nettyHttpRequest.headers().add(HttpHeaderNames.CONTENT_LENGTH, HttpHeaderValues.ZERO);
    nettyHttpRequest.headers().add(HttpHeaderNames.CONNECTION, HttpHeaderValues.KEEP_ALIVE);
    try {
        long st = System.currentTimeMillis();
        encodeHeaders(nettyHttpRequest.headers(), buf);
        long et = System.currentTimeMillis();
        System.out.println("cost time :"+(et-st));
    }catch (Exception e){

    }

}


protected static void encodeHeaders(HttpHeaders headers, ByteBuf buf) throws Exception {
    Iterator<Map.Entry<CharSequence, CharSequence>> iter = headers.iteratorCharSequence();
    while (iter.hasNext()) {
        Map.Entry<CharSequence, CharSequence> header = iter.next();
        long st = System.currentTimeMillis();
        encoderHeader(header.getKey(), header.getValue(), buf);
        long et = System.currentTimeMillis();
        System.out.println("encode header "+header.getKey()+" value "+header.getValue()+" cost time :"+(et-st));
    }
}


public static void encoderHeader(CharSequence name, CharSequence value, ByteBuf buf) throws Exception {
    final int nameLen = name.length();
    final int valueLen = value.length();
    final int entryLen = nameLen + valueLen + 4;
    buf.ensureWritable(entryLen);
    int offset = buf.writerIndex();
    writeAscii(buf, offset, name, nameLen);
    offset += nameLen;
    buf.setByte(offset ++, ':');
    buf.setByte(offset ++, ' ');
    writeAscii(buf, offset, value, valueLen);
    offset += valueLen;
    buf.setByte(offset ++, '\r');
    buf.setByte(offset ++, '\n');
    buf.writerIndex(offset);
}

private static void writeAscii(ByteBuf buf, int offset, CharSequence value, int valueLen) {
    if (value instanceof AsciiString) {
        long st = System.currentTimeMillis();
        ByteBufUtil.copy((AsciiString) value, 0, buf, offset, valueLen);
        long et = System.currentTimeMillis();
        //System.out.println("writeAscii header "+value+" value  cost time :"+(et-st));

    } else {

        writeCharSequence(buf, offset, value, valueLen);

    }
}

private static void writeCharSequence(ByteBuf buf, int offset, CharSequence value, int valueLen) {
    for (int i = 0; i < valueLen; ++i) {
        buf.setByte(offset ++, c2b(value.charAt(i)));
    }
}

Netty version

4.1.9

JVM version (e.g. java -version)

OS version (e.g. uname -a)

[slandelle]

Several comments:

• Never use System. currentTimeMillis() for measuring short durations: it’s a wall clock that can drift and can be updated any time by NTP. With a fixed version of your sample using System. nanoTime(), I have a cost of 3ms on my machine.
• If you want to build microbenchmarks, use JMH

[normanmaurer]

Please reopen once you have a proper jmh benchmark …