[Serializer] CacheClassMetadataFactory performance

[martiis]

Symfony version(s) affected: 4.1.3 (havent test other)

Description
IDK if it was discussed in the past but recently i was checking symfony serializer (ObjectNormalizer) performance, and in dev env it was faster than in prod. I have configured opcache just like in docs, xdebug disabled.

My test is serializing 1000 objects with various scalar value properies + one property is an object + one property holds 5-15 small objects in array.

Serialize took about 2184 ms prod env, 152 ms dev env.

How to reproduce
My actual test https://github.com/martiis/symfony-serialization-bench/blob/master/src/Command/BenchSymfonySerializerCommand.php#L78

Possible Solution
Found out that in prod CacheClassMetadataFactory does not keep loaded classes like ClassMetadataFactory and everytime it goes into file system checking cache. I thought opcache should fix this but it didint or maybe i missed something? if I put $loadedClasses property in CacheClassMetadataFactory performance back as in dev env.

Additional context
Opcache config

opcache.memory_consumption=256
opcache.max_accelerated_files=20000
opcache.interned_strings_buffer = 16

[martiis]

Blackfire graphs:

• dev
• prod

[GuilhemN]

A radical but efficient solution would be #22051 :)

[nicolas-grekas]

There's a regression identified in #28457 (comment).
Someone would need to have a look.

[martiis]

This will improve perf, but later I noticed that I haven't enabled opcache for cli, which improved performance (cant remember by how much atm, but near as dev env), because PhpFilesAdapter is only working with opcache enabled, else fallbacks to filesystem adapter. CacheClassMetadataFactory always goes into cache adapter, thats why my test was so slow.

[xabbuh]

let's close then as the issue seems to be resolved