Latency of flushAndWrite operation

[diamant...@gmail.com]

Hi, 

I am wondering if anyone can share their insights into netty writeAndFlush latency with me. I am running netty v4.1.0 CR7 with epoll handling about 45,000 QPS of HTTP traffic. Hardware environment is 24 cores with 64GB RAM. Through instrumentation, I am observing a 99th percentile latency of about 10ms for writeAndFlush invocations. I am measuring this by recording the time prior to invoking writeAndFlush and attaching a listener for operationComplete. Does a 10ms 99th percentile latency for writeAndFlush seem reasonable to others? It seems like a significant cost for writing to a socket and I am looking to identify whether or not I can improve my usage of netty.

Thank you,

Michael

[Norman Maurer]

Do you write from outside the EventLoop or not? Like calling Channel.writeAndFlush(...) from outside a ChannelHandler implementation?

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[diamant...@gmail.com]

Hi Norman, 

Thank you for getting back to me.  Yes, in this scenario I am invoking writeAndFlush from outside the EventLoop.

Michael

[Arnab Biswas]

[Opening an old thread.....]

What is the best practice here? I am assuming that invoking writeAndFlush() from a channelHandler is good (following example) :

public class MyStreamHandler extends ChannelInboundHandlerAdapter {

//Some code 

    @Override

    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {

    //some code

final ChannelFuture future = this.channel.writeAndFlush(content);

future.addListener(new WriteCompleteListener(..);

//some other code

    }

} 

Or  invoking writeAndFlush from outside the EventLoop is the best practice? I am little confused.

Thanks,

Arnab

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