2017年10月27日、モノビットエンジン勉強会inサイバーコネクトツーにて、中嶋謙互が講演しました「ネットワークゲームにおける TCPとUDPの使い分け」のスライドになります。ネットワークゲームを製作する際にご参考頂けますと幸いです。 登壇者: 株式会社モノビット 取締役 CTO 中嶋謙互

At this point we have a TCP/IP stack that is able to communicate to other hosts in the Internet. The implementation so far has been fairly straight-forward, but missing a major feature: Reliability. Namely, our TCP does not guarantee the integrity of the data stream it presents to applications. Even establishing the connection can fail if the handshake packets are lost in transit. Introducing reli
A coworker was experiencing a strange problem with their Internet connection at home. Large downloads from most sites worked fine. The exception was that downloads from a Amazon S3 would get up to a good speed (500Mbps), stall completely for a few seconds, restart for a while, stall again, and eventually hang completely. The problem seemed to be specific to S3, downloads from generic AWS VMs were
SO_REUSEPORT Scaling Techniques for Servers with High Connection Rates Ying Cai ycai@google.com Problems Servers with high connection/transaction rates TCP servers, e.g. web server UDP servers, e.g. DNS server On multi-core systems, using multiple servicing threads, e.g. one thread per servicing core. The single server socket becomes bottleneck Cache line bounces Hard to achieve load balance Thing
Previous Next Table of Contents 2. クライアントとサーバ(TCP/SOCK_STREAM)両方に関する質問 2.1 相手側のソケットが閉じられたことをどうやって知ることができますか? Andrew Gierth 氏 ( [email protected]emon.co.uk) より: 私の知る限り… 相手側が (SO_LINGER を使ったややこしいことをしないで) close() するか終了したとすると、こちらの read() の呼び 出しは 0 を返すはずです。同じ場合で、write() 呼び出しで何が 起こるかは、もうちょっとわかりづらいです。直後の呼び出し時ではな く、その次の呼び出し時にEPIPE が返るでしょう。 もし相手が再起動するか l_onoff = 1, l_linger = 0 を設定して から閉じたとすると、read() からは(
Did you know your TCP/IP stack leaks information on your physical location? This website demonstrates IP address geo-location by passively measuring TCP/IP round-trip times of web requests made to a few servers spread around the world. The measurements are then used to approximate possible physical distances to the servers, and finally drawn on a Google Map. The common area of all circles (that is
The other day I learned about a new (to me) exciting Linux system call! (for newcomers, a system call is an operation you can ask the operating system to do). This one seems really important to know about if you’re configuring a webserver! So let’s learn about it. Before this, I knew about basic system calls like open and read for files, and sendto and recvfrom for networking. And a few fancier th
この記事はTCPの 全て を理解する、あるいは 『TCP/IP Illustrated』 (訳注:日本語版: 『詳解TCP/IP〈Vol.1〉プロトコル』 )を読破しようとか、そういうことではありません。ほんの少しのTCPの知識がどれほど欠かせないものなのかについてお話します。まずはその理由をお話しましょう。 私が Recurse Center で働いているとき、PythonでTCPスタックを書きました( またPythonでTCPスタックを書いたらどうなるかについても書きました )。それはとても楽しく、ためになる経験でした。またそれでいいと思っていたんです。 そこから1年ぐらい経って、仕事で、誰かが「NSQへメッセージを送ったんだが、毎回40ミリ秒かかる」とSlackに投稿しているのを見つけました。私はこの問題についてすでに1週間ほど考え込んでいましたが、さっぱり答えがでませんでした。 こ
3. • B3 k6 z 2 l • mTCP +4Intel4DPDK wi • github mTCP+4DPDK orz • Key4Value4Store w k Linux l • RADIS → • d v orz • Memcached → • d 3 4. A G 7 LNPMXXT 4 0 0.2 0.4 0.6 0.8 1 0 20 40 60 80 100 Key size (bytes) Key size CDF by appearance USR APP ETC VAR SYS 0 0.2 0.4 0.6 0.8 1 1 10 100 1000 10000 100000 1e+06 Value size (bytes) Value Size CDF by appearance USR APP ETC VAR SYS 0 0.2 0.4 0.6 0.8 1 1 10
TCP Tuning for HTTP draft-stenberg-httpbis-tcp-02 Abstract This document records current best practice for using all versions of HTTP over TCP. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working docum
Sep 10, 201470 likes19,367 viewsAI-enhanced description Chartbeat measures and monetizes attention on the web. They were experiencing slow load times and TCP retransmissions due to default system settings. Tuning various TCP, NGINX and EC2 ELB settings like increasing buffers, disabling Nagle's algorithm, and enabling HTTP keep-alive resolved the issues and improved performance. These included tun
(WEB401) Optimizing Your Web Server on AWS | AWS re:Invent 2014 Tuning your EC2 web server will help you to improve application server throughput and cost-efficiency as well as reduce request latency. In this session we will walk through tactics to identify bottlenecks using tools such as CloudWatch in order to drive the appropriate allocation of EC2 and EBS resources. In addition, we will also be
November 21, 2015 This isn’t about understanding everything about TCP or reading through TCP/IP Illustrated. It’s about how a little bit of TCP knowledge is essential. Here’s why. When I was at the Recurse Center, I wrote a TCP stack in Python (and wrote about what happens if you write a TCP stack in Python). This was a fun learning experience, and I thought that was all. A year later, at work, so
A customer reported an unusual problem with our CloudFlare CDN: our servers were responding to some HTTP requests slowly. Extremely slowly. 30 seconds slowly. This happened very rarely and wasn't easily reproducible. To make things worse all our usual monitoring hadn't caught the problem. At the application layer everything was fine: our NGINX servers were not reporting any long running requests.
You can find (just about) anything on Medium — apparently even a page that doesn’t exist. Maybe these stories will take you somewhere new?
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