benchmarking

问题 I need to read a file one character at a time and I'm using the read() method from BufferedReader . * I found that read() is about 10x slower than readLine() . Is this expected? Or am I doing something wrong? Here's a benchmark with Java 7. The input test file has about 5 million lines and 254 million characters (~242 MB) **: The read() method takes about 7000 ms to read all the characters: @Test public void testRead() throws IOException, UnindexableFastaFileException{ BufferedReader fa= new

问题 In my scenario, the methods in benchmark should run sequentially in one thread and modify the state in order. For example, there is a List<Integer> called num in the benchmark class. What I want is: first, run add() to append a number into the list. Then, run remove() to remove the number from the list. The calling sequence must be add() --> remove() . If remove() runs before add() or they run concurrently, they would raise exceptions because there's no element in the list. That is, add() and

问题 In my scenario, the methods in benchmark should run sequentially in one thread and modify the state in order. For example, there is a List<Integer> called num in the benchmark class. What I want is: first, run add() to append a number into the list. Then, run remove() to remove the number from the list. The calling sequence must be add() --> remove() . If remove() runs before add() or they run concurrently, they would raise exceptions because there's no element in the list. That is, add() and

问题 I did a small benchmark test to compare Couchbase (running in Win) with Redis and MySql (EDIT: added Aerospike to test) We are inserting 100 000 JSON "documents" into three db/stores: Redis (just insert, there is nothing else) Couchbase (in-memory Ephemeral buckets, JSON Index on JobId) MySql (Simple table; Id (int), Data (MediumText), index on Id) Aerospike (in-memory storage) The JSON file is 67 lines, about 1800 bytes. INSERT: Couchbase: 60-100 seconds (EDIT: seems to vary quite a bit!)

问题 I was messing around with the benchmark site jfprefs and created my own benchmark at http://jsperf.com/prefix-or-postfix-increment/9. The benchmarks are variations of Javascript for loops, using prefix and postfix incrementors and the Crockford jslint style of not using an in place incrementor. for (var index = 0, len = data.length; index < len; ++index) { data[index] = data[index] * 2; } for (var index = 0, len = data.length; index < len; index++) { data[index] = data[index] * 2; } for (var

问题 I would like to calculate how long an async function ( async / await ) is taking in JavaScript. One could do: const asyncFunc = async function () {}; const before = Date.now(); asyncFunc().then(() => { const after = Date.now(); console.log(after - before); }); However, this does not work, because promises callbacks are run in a new microtask. I.e. between the end of asyncFunc() and the beginning of then(() => {}) , any already queued microtask will be fired first, and their execution time

问题 I would like to calculate how long an async function ( async / await ) is taking in JavaScript. One could do: const asyncFunc = async function () {}; const before = Date.now(); asyncFunc().then(() => { const after = Date.now(); console.log(after - before); }); However, this does not work, because promises callbacks are run in a new microtask. I.e. between the end of asyncFunc() and the beginning of then(() => {}) , any already queued microtask will be fired first, and their execution time

问题 List of Nvidia GPU - GeForce 900 Series - there is written that: 4 Single precision performance is calculated as 2 times the number of shaders multiplied by the base core clock speed. I.e. for example for GeForce GTX 970 we can calculate performance: 1664 Cores * 1050 MHz * 2 = 3 494 GFlops peak (3 494 400 MFlops) This value we can see in column - Processing Power (peak) GFLOPS - Single Precision. But why we must multiple by 2 ? There is written: http://devblogs.nvidia.com/parallelforall

问题 List of Nvidia GPU - GeForce 900 Series - there is written that: 4 Single precision performance is calculated as 2 times the number of shaders multiplied by the base core clock speed. I.e. for example for GeForce GTX 970 we can calculate performance: 1664 Cores * 1050 MHz * 2 = 3 494 GFlops peak (3 494 400 MFlops) This value we can see in column - Processing Power (peak) GFLOPS - Single Precision. But why we must multiple by 2 ? There is written: http://devblogs.nvidia.com/parallelforall

问题 List of Nvidia GPU - GeForce 900 Series - there is written that: 4 Single precision performance is calculated as 2 times the number of shaders multiplied by the base core clock speed. I.e. for example for GeForce GTX 970 we can calculate performance: 1664 Cores * 1050 MHz * 2 = 3 494 GFlops peak (3 494 400 MFlops) This value we can see in column - Processing Power (peak) GFLOPS - Single Precision. But why we must multiple by 2 ? There is written: http://devblogs.nvidia.com/parallelforall