Re: OPcache compilation performance regression in PHP 5.6/7 with huge classes

On 14 Mar 2017, at 16:39, Nikita Popov <nikita.ppv@gmail.com> wrote: > > On Tue, Mar 14, 2017 at 11:29 AM, David Zuelke <dz@heroku.com> wrote: >> Hi all, >> >> There appears to be a performance regression in the CFG and DFA based optimization passes >> of OPcache in PHP 5.6+ when loading huge classes (such as those generated by Symfony's routing >> component) for the first time. >> >> .... >> >> Is this slowness with a cold cache expected/accepted, or does that qualify as a bug? > > Yes, this is a bug. Optimization should never be this slow. > > From a quick perf run, the problem in the DFA pass is that TI is quadratic in the number of > calls (as call lookup is implemented as a linear scan). This can be fixed with a more efficient map > lookup. > The problem in the CFG pass is that a large buffer is zeroed repeatedly. Alright, thanks! I opened a bug for it: https://bugs.php.net/bug.php?id=74250