Hi Brent, Preloading had intention to completely eliminate opcache overhead, but because of limitations it wasn't able to preload classes with unresolved constants, typed properties and covariant checks.
This PR makes these preloading limitations less strict and adds transparent inheritance cache. Inheritance cache eliminates only part of redundancy, in comparison to preloading. It should be a bit slower, but it will work out of the box. Thanks. Dmitry. On Tue, Feb 9, 2021 at 8:40 AM Brent Roose <bre...@stitcher.io> wrote: > Hey Dmitry > > Out of curiousity: how does this compare to preloading? From what I > understand preloading also links classes, which was one of the most > important differences between preloading files and simply storing them in > opcache. Does this change mean that preloading becomes much less relevant > since class linking can now also happen at runtime? > > Kind regards > Brent > > > On 5 Feb 2021, at 15:03, Dmitry Stogov <dmitrysto...@gmail.com> wrote: > > > > Hi, > > > > I'm glad to present the result of my recent work - Inheritance Cache. > > > > https://github.com/php/php-src/pull/6627 > > > > This is a new transparent technology that eliminates overhead of PHP > class > > inheritance. > > > > PHP classes are compiled and cached (by opcahce) separately, however > their > > "linking" was done at run-time - on each request. The process of > "linking" > > may involve a number of compatibility checks and borrowing > > methods/properties/constants form parent and traits. This takes > significant > > time, but the result is the same on each request. > > > > Inheritance Cache performs "linking" for unique set of all the depending > > classes (parent, interfaces, traits, property types, method types > involved > > into compatibility checks) once and stores result in opcache shared > memory. > > As a part of the this patch, I removed limitations for immutable classes > > (unresolved constants, typed properties and covariant type checks). So > now > > all classes stored in opcache are "immutable". They may be lazily loaded > > into process memory, if necessary, but this usually occurs just once (on > > first linking). > > > > The patch shows 8% improvement on Symphony "Hello World" app. > > > > I'm going to merge this patch into master on next week. > > Please review and give your comments. > > > > Thanks. Dmitry. > >
