design time - Page 537 - Developer IT

UNIX timestamp always in GMT?

- by bn

UNIX timestamp always in GMT? I tried to run php function time() and when I tried to convert the unix timestamp from the time() function, the output is not similar to the computer time. Thank You

[Android] For-Loop Performance Oddity

I just noticed something concerning for-loop performance that seems to fly in the face of the recommendations given by the Google Android team. Look at the following code: package com.jackcholt; import android.app.Activity; import android.os.Bundle; import android.util.Log; public class Main extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); loopTest(); finish(); } private void loopTest() { final long loopCount = 1228800; final int[] image = new int[8 * 320 * 480]; long start = System.currentTimeMillis(); for (int i = 0; i < (8 * 320 * 480); i++) { image[i] = i; } for (int i = 0; i < (8 * 320 * 480); i++) { image[i] = i; } Log.i("loopTest", "Elapsed time (recompute loop limit): " + (System.currentTimeMillis() - start)); start = System.currentTimeMillis(); for (int i = 0; i < 1228800; i++) { image[i] = i; } for (int i = 0; i < 1228800; i++) { image[i] = i; } Log.i("loopTest", "Elapsed time (literal loop limit): " + (System.currentTimeMillis() - start)); start = System.currentTimeMillis(); for (int i = 0; i < loopCount; i++) { image[i] = i; } for (int i = 0; i < loopCount; i++) { image[i] = i; } Log.i("loopTest", "Elapsed time (precompute loop limit): " + (System.currentTimeMillis() - start)); } } When I run this code I get the following output in logcat: I/loopTest( 726): Elapsed time (recompute loop limit): 759 I/loopTest( 726): Elapsed time (literal loop limit): 755 I/loopTest( 726): Elapsed time (precompute loop limit): 1317 As you can see the code that seems to recompute the loop limit value on every iteration of the loop compares very well to the code that uses a literal value for the loop limit. However, the code that uses a variable which contains the precomputed value for the loop limit is significantly slower than either of the others. I'm not surprised that accessing a variable should be slower that using a literal but why does code that looks like it should be using two multiply instructions on every iteration of the loop so comparable in performance to a literal? Could it be that because literals are the only thing being multiplied, the Java compiler is optimizing out the multiplication and using a precomputed literal?

Search Results

Search found 69140 results on 2766 pages for 'design time'.

Page 537/2766 | < Previous Page | 533 534 535 536 537 538 539 540 541 542 543 544 | Next Page >

- by bn

- by Jack Holt

- by Sebastian

- by Rajakumar

- by ephieste

- by niklassaers

- by Lindsay Fisher

- by Kazu

- by Morgan Cheng

- by Daniil

- by Hojo

- by sjngm

- by Khalid Omar

- by Barakat

- by Midnight

- by webworm

- by NPehrsson

- by Steven

- by nettguy

- by Morgan Cheng

- by Ramakrishnan

- by Andrew

- by asmaier

- by Klaas Jan

- by himanshu rawat

< Previous Page | 533 534 535 536 537 538 539 540 541 542 543 544 | Next Page >