Feature Request: re-enable php opcache for dev-environments?

[schuhwerk]

Terms

• I have read the guidelines for Contributing to Roots Projects
• This request is not a duplicate of an existing issue
• This is not a personal support request that should be posted on the Roots Discourse community

Summary

Re-enabling opcache for dev decreases load time (in my case) by ~30%.

Motivation

I'm developing on Windows and my VM is slow (0.3s on production vs. 2.5s on dev for the same page).
I tried re-enabling opcache and obviously ran into the problem discussed here.

So I added/changed the following settings (group_vars/development/php.yml):

php_opcache_enable: 1
php_opcache_validate_timestamps: 1
php_opcache_revalidate_freq: 1

This brings down loading times for the same page (mentioned above) to 1.7s.

I don't have any problems with file-changes. In my case php_opcache_revalidate_freq can even stay at 60. This would even bring the dev-configuration closer to the one on the production environment.

I'm not sure, how it is for other environments, so we might be able to collect different experiences for other OSes/Configurations here.

Additional Context

I used several runs of Performance Insights (within Chrome's dev-tools) for the benchmarks.

[swalkinshaw]

🤔 interesting idea! Basically the theory is that having opcaching enabled is worthwhile even when re-validating every 1 second.

I'm also curious about this setting: opcache.enable_file_override bool

When enabled, the opcode cache will be checked for whether a file has already been cached when file_exists(), is_file() and is_readable() are called. This may increase performance in applications that check the existence and readability of PHP scripts, but risks returning stale data if opcache.validate_timestamps is disabled.

Because we'd always have validate_timestamps enabled, it seems safe. Want to test that out as well to see if it makes a difference?

[schuhwerk]

I wrote a small script ...

#!/bin/bash
# benchmark.sh
URL="$1" # Pass as firs parameter or just add an url here...
COUNT=10
TOTAL=0
for i in $(seq 1 $COUNT); do
	T=$( curl -o /dev/null -s -w '%{time_total}' "$URL" )
	echo -e "$i/$COUNT:\t$T"
	TOTAL=$( awk "BEGIN{ print $TOTAL + $T }" )
done
echo -e "---\nTotal:\t$( awk "BEGIN{ print $TOTAL/$COUNT }" )"

... and did some benchmarks in the following manner:

sudo vim /etc/php/8.0/fpm/php.ini       # change the value
sudo service php8.0-fpm restart         # then restart php.ini
bash benchmark.sh "https://example.com" # then run the script

tldr.:

• The first value is always bigger, because the cache has to be initialized.
• enable_file_override doesn't significantly change things for me.

---

I use this ini-setting (below) as the default setting, and only show changed values (in the following benchmarks).

opcache.enable = 1
opcache.enable_cli = 1
opcache.memory_consumption = 512
opcache.interned_strings_buffer = 8
opcache.max_accelerated_files = 10000
opcache.revalidate_freq = 1
opcache.fast_shutdown = 1
opcache.validate_timestamps = 1
opcache.enable_file_override = 1

1/10:   2.192602
2/10:   1.417862
3/10:   1.329829
4/10:   1.352817
5/10:   1.350337
6/10:   1.214131
7/10:   1.529780
8/10:   1.332163
9/10:   1.487570
10/10:  1.309430
---
Total:  1.45166

Another run with the same settings:

1/10:   2.212923
2/10:   1.270493
3/10:   1.220274
4/10:   1.247268
5/10:   1.277368
6/10:   1.330988
7/10:   1.247622
8/10:   1.161211
9/10:   1.512393
10/10:  1.280042
---
Total:  1.37605

---

opcache.validate_timestamps = 0

1/10:   2.037866
2/10:   1.356562
3/10:   1.318341
4/10:   1.239954
5/10:   1.335589
6/10:   1.267463
7/10:   1.441167
8/10:   1.315683
9/10:   1.320554
10/10:  1.295416
---
Total:  1.39286

---

opcache.enable = 0

1/10:   1.990889
2/10:   2.220091
3/10:   1.991241
4/10:   2.000759
5/10:   2.037611
6/10:   1.922285
7/10:   2.066977
8/10:   1.986670
9/10:   2.048466
10/10:  2.009548
---
Total:  2.02746

---

opcache.enable_file_override = 0

1/10:   2.365654
2/10:   1.445723
3/10:   1.356475
4/10:   1.493420
5/10:   1.291487
6/10:   1.497339
7/10:   1.313832
8/10:   1.460188
9/10:   1.255856
10/10:  1.324482
---
Total:  1.48045

---

opcache.revalidate_freq = 60

1/10:   2.197011
2/10:   1.305936
3/10:   1.235971
4/10:   1.205744
5/10:   1.371293
6/10:   1.160303
7/10:   1.276416
8/10:   1.170768
9/10:   1.216995
10/10:  1.226870
---
Total:  1.33673

---

opcache.revalidate_freq = 60
opcache.validate_timestamps = 0

1/10:   2.101342
2/10:   1.249363
3/10:   1.258679
4/10:   1.228603
5/10:   1.195424
6/10:   1.224175
7/10:   1.217903
8/10:   1.270338
9/10:   1.298442
10/10:  1.199673
---
Total:  1.32439

[swalkinshaw]

I ran your script and saw similar numbers (but much lower) using a default install and default theme:

Without opcache:

1/10:	0.428497
2/10:	0.332736
3/10:	0.328061
4/10:	0.326045
5/10:	0.323269
6/10:	0.333123
7/10:	0.323723
8/10:	0.341296
9/10:	0.338455
10/10:	0.326333
---
Total:	0.340153

With opcache enabled:

1/10:	0.579579
2/10:	0.157527
3/10:	0.156097
4/10:	0.152035
5/10:	0.165091
6/10:	0.150111
7/10:	0.164437
8/10:	0.170205
9/10:	0.150592
10/10:	0.151921
---
Total:	0.199759

This was true even with revalidate_freq = 0. If that's true, then it would be the safest option in development since files are checked every request eliminating any time lag of cached files.

[swalkinshaw]

#1447 is up but we'll do some more testing.