We've been curious for a while about the overhead due to array setup time, especially in the context of language files. Although Turck caches the bytecode, the interpreter still has to process that bytecode and allocate the array data structures. How long does this take?

The answer is 4ms, to load both French and English messages.

Criticism of my method would be welcome, I'll present it here in full. I used two files, slow.php:

<?php

define('MEDIAWIKI', 1); function wfSuppressWarnings() {} function wfRestoreWarnings() {}

$wgLanguageCode = 'fr'; $IP = '/apache/common/php-1.5'; ini_set('include_path', "$IP/languages"); require_once("$IP/languages/Language.php");

print time() . "\n";

?>

And fast.php, which is exactly the same except without the require_once:

<?php

define('MEDIAWIKI', 1); function wfSuppressWarnings() {} function wfRestoreWarnings() {}

$wgLanguageCode = 'fr'; $IP = '/apache/common/php-1.5'; ini_set('include_path', "$IP/languages");

print time() . "\n";

?>

Turck MMCache only works for the apache module SAPI, so I benchmarked these two files using ab. I used hypatia, which is a 3 GHz P4. It was otherwise idle. Here is the output:

[0625][tstarling@hypatia:~]$ ab -Xlocalhost:80 -n10000 http://en.wikipedia.org/w/benchmark/fast.php This is ApacheBench, Version 2.0.41-dev <$Revision: 1.141 $> apache-2.0 Copyright (c) 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/ Copyright (c) 1998-2002 The Apache Software Foundation, http://www.apache.org/

Benchmarking en.wikipedia.org [through localhost:80] (be patient) Completed 1000 requests Completed 2000 requests Completed 3000 requests Completed 4000 requests Completed 5000 requests Completed 6000 requests Completed 7000 requests Completed 8000 requests Completed 9000 requests Finished 10000 requests

Server Software: Apache Server Hostname: en.wikipedia.org Server Port: 80

Document Path: /w/benchmark/fast.php Document Length: 11 bytes

Concurrency Level: 1 Time taken for tests: 7.759175 seconds Complete requests: 10000 Failed requests: 0 Write errors: 0 Total transferred: 1530000 bytes HTML transferred: 110000 bytes Requests per second: 1288.80 [#/sec] (mean) Time per request: 0.776 [ms] (mean) Time per request: 0.776 [ms] (mean, across all concurrent requests) Transfer rate: 192.55 [Kbytes/sec] received

Connection Times (ms) min mean[+/-sd] median max Connect: 0 0 0.0 0 0 Processing: 0 0 12.0 0 851 Waiting: 0 0 12.0 0 851 Total: 0 0 12.0 0 851

Percentage of the requests served within a certain time (ms) 50% 0 66% 0 75% 0 80% 0 90% 0 95% 0 98% 0 99% 0 100% 851 (longest request)

[0628][tstarling@hypatia:/apache/common/live-1.5/benchmark]$ ab -Xlocalhost:80 -n10000 http://en.wikipedia.org/w/benchmark/slow.php This is ApacheBench, Version 2.0.41-dev <$Revision: 1.141 $> apache-2.0 Copyright (c) 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/ Copyright (c) 1998-2002 The Apache Software Foundation, http://www.apache.org/

Benchmarking en.wikipedia.org [through localhost:80] (be patient) Completed 1000 requests Completed 2000 requests Completed 3000 requests Completed 4000 requests Completed 5000 requests Completed 6000 requests Completed 7000 requests Completed 8000 requests Completed 9000 requests Finished 10000 requests

Server Software: Apache Server Hostname: en.wikipedia.org Server Port: 80

Document Path: /w/benchmark/slow.php Document Length: 11 bytes

Concurrency Level: 1 Time taken for tests: 47.707920 seconds Complete requests: 10000 Failed requests: 0 Write errors: 0 Total transferred: 1530000 bytes HTML transferred: 110000 bytes Requests per second: 209.61 [#/sec] (mean) Time per request: 4.771 [ms] (mean) Time per request: 4.771 [ms] (mean, across all concurrent requests) Transfer rate: 31.32 [Kbytes/sec] received

Connection Times (ms) min mean[+/-sd] median max Connect: 0 0 0.0 0 0 Processing: 4 4 0.5 4 29 Waiting: 0 4 0.5 4 28 Total: 4 4 0.5 4 29

Percentage of the requests served within a certain time (ms) 50% 4 66% 4 75% 4 80% 4 90% 4 95% 4 98% 4 99% 6 100% 29 (longest request)