latency

Typical UDP latency on iPhone over 3G - are my numbers right?

由 百般思念 提交于 2019-12-01 12:32:51
问题 In order to evaluate TCP versus UDP on the iPhone, I wrote a small echo server on my computer and used the AsyncUdpSocket library on the iPhone, but latencies are coming out surprisingly large and I wonder if there is something wrong with my implementation somehow. My setup has a wifi-router (Apple Airport) which has an external static IP. The port used by the echo server is forwarded to my development computer. I used two different setups: iPhone -> Wifi -> Wifi Router -> Wifi -> Computer

Throughput and Latency on Apache Flink

由 ▼魔方 西西 提交于 2019-12-01 11:18:53
I have written a very simple java program for Apache Flink and now I am interested in measuring statistics such as throughput (number of tuples processed per second) and latency (the time the program needs to process every input tuple). StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment(); env.readTextFile("/home/LizardKing/Documents/Power/Prova.csv") .map(new MyMapper().writeAsCsv("/home/LizardKing/Results.csv"); JobExecutionResult res = env.execute(); I know that Flink exposes some metrics: https://ci.apache.org/projects/flink/flink-docs-release-1.2

Throughput and Latency on Apache Flink

由 半城伤御伤魂 提交于 2019-12-01 07:27:52
问题 I have written a very simple java program for Apache Flink and now I am interested in measuring statistics such as throughput (number of tuples processed per second) and latency (the time the program needs to process every input tuple). StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment(); env.readTextFile("/home/LizardKing/Documents/Power/Prova.csv") .map(new MyMapper().writeAsCsv("/home/LizardKing/Results.csv"); JobExecutionResult res = env.execute(); I know

java midi latency

由 蹲街弑〆低调 提交于 2019-12-01 02:48:15
问题 I´m trying to make a java application that is able to play notes on the computer after detecting a midi device. Once I get the desired midi device I´m seting the receiver to which the device´s transmitter will deliver MIDI messages. device.getTransmitter().setReceiver( new MyReceiver()) ; class MyReceiver looks like: public class MyReceiver implements Receiver { MidiChannel[] channels ; public MyReceiver (){ try { Synthesizer synthesizer = MidiSystem.getSynthesizer(); synthesizer.open();

Timers to measure latency

由 馋奶兔 提交于 2019-11-30 17:06:16
问题 When measuring network latency (time ack received - time msg sent) in any protocol over TCP, what timer would you recommend to use and why? What resolution does it have? What are other advantages/disadvantages? Optional: how does it work? Optional: what timer would you NOT use and why? I'm looking mostly for Windows / C++ solutions, but if you'd like to comment on other systems, feel free to do so. (Currently we use GetTickCount(), but it's not a very accurate timer.) 回答1: This is a copy of

WebRTC getStat() API Set UP

由 只愿长相守 提交于 2019-11-30 15:21:22
问题 I am trying to use getStat() from WebRTC's api to see if it provides any useful info measure latency and other video streaming data. The problem is that there's not much info of how to use it. Even older existing examples are pretty rare but the api has changed since then. For example, my set up: peerconnection.getStats(function(stats) { console.log(stats); } )); This returns a RTCStatsResponse object with 2 functions RTCStatsResponse {result: function, namedItem: function} Trying to call

WebRTC getStat() API Set UP

由 南笙酒味 提交于 2019-11-30 13:50:33
I am trying to use getStat() from WebRTC's api to see if it provides any useful info measure latency and other video streaming data. The problem is that there's not much info of how to use it. Even older existing examples are pretty rare but the api has changed since then. For example, my set up: peerconnection.getStats(function(stats) { console.log(stats); } )); This returns a RTCStatsResponse object with 2 functions RTCStatsResponse {result: function, namedItem: function} Trying to call that result() function returns an array of RTCStatsReport objects with type 'googLibjingleSession' for the

Google App Engine JDO makePersistent latency

由 徘徊边缘 提交于 2019-11-29 22:50:38
问题 I have a problem with the Google App Engine JDO implementation that I cannot figure out. The documentation (http://code.google.com/intl/sv-SE/appengine/docs/java/datastore/jdo/creatinggettinganddeletingdata.html) states "The call to makePersistent() is synchronous, and doesn't return until the object is saved and indexes are updated." but my experience differs. I want to save (makePersistent) an object into the datastore. When the save is complete I want to be able to fetch it (Query execute)

Measuring ping latency of a server - Python

由 十年热恋 提交于 2019-11-29 14:48:57
问题 I have a list of server IP addresses , I need to check if each one is online and how long the latency is. I haven't found any straight forward ways of implementing this, and there seems to be a few problems in calculating latency accurately. Any ideas? 回答1: If you are already comfortable with parsing strings, you can use the subprocess module to get the data you are looking for into a string, like this: >>> import subprocess >>> p = subprocess.Popen(["ping.exe","www.google.com"], stdout =

Handeling Latency in MySQL Transactions

由 a 夏天 提交于 2019-11-29 12:00:34
The Problem I'm trying to figure out how to correctly set up a transaction in a database, and account for potential latency. The Setup In my example I have a table of users , keys , where each user can have multiple keys, and a config table that dictates how many keys each user is allowed to have. I want to run a stored procedure that: figures out if the given user is allowed to request a key. get an available, unclaimed key . attempts to redeem the key for the given user. the pseudocode for the procedure would be: START TRANSACTION (1) CALL check_permission(...,@result); IF (@result = 'has
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