micro.md

local

Attribute	Value
Environment	local
Runner	docker
Architecture	x86_64
CPU	16 cores
RAM	30 GB
Kernel	5.11.0-1022-aws
OS	Ubuntu 20.04.3 LTS
Time	2022-05-13 16:02:00

Micro 1 - 15 consecutive runs, 20 requests (sec)

PHP	Min	Max	Std dev	Average	Average diff %	Median	Median diff %	Memory
PHP 8.x long-closure.php	0.35877	0.36328	0.00114	0.36028	0.00%	0.36005	0.00%	24.22 MB
PHP 8.x-patch1 short-closure.php	0.41705	0.42313	0.00132	0.41881	16.25%	0.41879	16.31%	24.55 MB
PHP 8.x-patch1 long-closure.php	0.37323	0.37655	0.00077	0.37417	3.86% [0]	0.37416	3.92%	24.52 MB
PHP 8.x-patch2 short-closure.php	0.36084	0.36513	0.00111	0.36236	0.58%	0.36199	0.54%	24.37 MB
PHP 8.x-patch2 long-closure.php	0.36080	0.36333	0.00084	0.36199	0.47%	0.36229	0.62%	24.29 MB

Micro 2 - 1 consecutive runs, 1 requests (sec)

PHP	Min	Max	Std dev	Average	Average diff %	Median	Median diff %	Memory
PHP 8.x long-closure.php	0.02384	0.02384	0.00000	0.02384	0.00%	0.02384	0.00%	32.27 MB
PHP 8.x-patch1 short-closure.php	0.08186	0.08186	0.00000	0.08186	243.37%	0.08186	243.37%	420.01 MB
PHP 8.x-patch1 long-closure.php	0.02699	0.02699	0.00000	0.02699	13.22% [0]	0.02699	13.22%	32.07 MB
PHP 8.x-patch2 short-closure.php	0.02345	0.02345	0.00000	0.02345	-1.65% [0]	0.02345	-1.65%	32.16 MB
PHP 8.x-patch2 long-closure.php	0.02335	0.02335	0.00000	0.02335	-2.06% [0]	0.02335	-2.06%	32.18 MB

PHP versions compared here:

• PHP 8.x is php-src master at commit 90a845c13f88072af3cc048731936e4a61b3ec3a
• PHP 8.x-patch1 is the original PR rebased on master: php/php-src#6246
• PHP 8.x-patch2 is the current PR: php/php-src#8330

The benchmarks:

• The micro 1 benchmark shows that extra captures increase ref counts, which can causes separations, and lead to extra CPU usage.
• The micro 2 benchmark shows that extra captures can cause extra memory usage.

Notes:

[0]: This difference is probably only due to variations.