Bootstrap flame graph

So that looks like mostly known issues, but to document them:

- routing event listener dependencies
- logger should be lazy service
- route preloading (while I think we need it, it might be worth an issue to make sure that's as optimized as it should be)\
- path alias whitelist similar comments to route pre-loading except we also have that in 7.x
- automated cron looks suspicious here too

- route preloading (while I think we need it, it might be worth an issue to make sure that's as optimized as it should be)\

Regarding that, it takes 10% on the unserialize() call. Even route preloading is nice, I wonder whether we could avoid the unserialization for the routes we don't use.

Here is a quick try for me previous IDEA

What jumped at me is the insane amount of services we load -- that requires finding the class and instantiating the class. I wonder how this would look with an APCu classloader to kill loadFile. And/or an xhprof/cachegrind number for how much time is spent in Composer\Autoload\ClassLoader::loadClass. I have a bad suspicion of 25-30%.

While it's useful to remind everyone just how bad the default composer classloader is for performance, it'd be more useful for the flamegraphs if we always use the APC class loader. Not clear from the issue summary what the case is here.

Filed an issue for that patch: #2381505: Unserialize preloaded routes on the fly

We have one for almost all the things already.

• routing event listener dependencies #2368275: EntityRouteEnhancer and ContentFormControllerSubscriber implicitly depend on too many services, #2368769: All route enhancers are run on every request
• logger should be lazy service #1973618: DIC: Lazy instantiation of service dependencies (ProxyManager for "proxy services")
• route preloading (while I think we need it, it might be worth an issue to make sure that's as optimized as it should be) #2381505: Unserialize preloaded routes on the fly
• path alias whitelist similar comments to route pre-loading except we also have that in 7.x
• automated cron looks suspicious here too #1973618: DIC: Lazy instantiation of service dependencies (ProxyManager for "proxy services")

On the left-side of the graph, the initialization of ApcuBackendFactory uses conf_path() instead of injecting the kernel which leads to (1) a call to \Drupal::hasRequest() (really slow, and totally unnecessary, just call \Drupal::request() and catch the exception, please) followed by a second construction of the request object from the globals.

It would be useful to get a graph excluding Symfony\Component\DependencyInjection\Container::get and Drupal\Core\DependencyInjection\Container::get. There might be ways to micro-optimize those, but they just add unnecessary noise on those graphs.

Nice observation!

On the left-side of the graph, the initialization of ApcuBackendFactory uses conf_path() instead of injecting the kernel which leads to (1) a call to \Drupal::hasRequest() (really slow, and totally unnecessary, just call \Drupal::request() and catch the exception, please) followed by a second construction of the request object from the globals.

Alright, lets fix more of the usecases of config_path() : #2384675: Deprecate conf_path()

It would be useful to get a graph excluding Symfony\Component\DependencyInjection\Container::get and Drupal\Core\DependencyInjection\Container::get. There might be ways to micro-optimize those, but they just add unnecessary noise on those graphs.

While this would be helpful, we have to keep in mind that initializing unnecessary dependencies is a thing we should really try to avoid, if possible, see the proxy issue.

While this would be helpful, we have to keep in mind that initializing unnecessary dependencies is a thing we should really try to avoid, if possible, see the proxy issue.

Of course. But those functions are not slow by themselves. Keeping them on the graph will lead to focusing on the wrong things and losing track of the big picture (see #2370667-19: [Meta] user/password flame graph for an example).

Oh yeah, I don't disagree with you at all here.

@moshe weitzman
Can you filter out some functions?

xhprof_enable(0, array('ignored_functions' =>  array('call_user_func', 'call_user_func_array')));

Is the way to do it.

Some related discussion in #2370667-19: [Meta] user/password flame graph and following (regarding Container::get())

On automated cron, you possibly want to disable poormans cron completely for this? Any serious site is going to do run cron manually.

No idea, but it eat the second half of my comment.

Also interesting: https://www.drupal.org/node/2353357

- Removes only reason for module handler in stream wrapper (although it will replace it with an event, which might be just as expensive?), but it will also allow to avoid loading the modules for routes like this. But that won't help much on most routes that invole theming.

Thank you for creating this issue to improve Drupal.

We are working to decide if this task is still relevant to a currently supported version of Drupal. There hasn't been any discussion here for over 8 years which suggests that this has either been implemented or is no longer relevant. Your thoughts on this will allow a decision to be made.

Since we need more information to move forward with this issue, the status is now Postponed (maintainer needs more info). If we don't receive additional information to help with the issue, it may be closed after three months.

Thanks!

Wanted to bump this 1 more time before closing.

I think it's fine to close this. There were actionable issues that were done, we have performance testing now, which doesn't provide exactly the same data, but whatever was shown in this specific flamegraph is long outdated. We can always create new issues if we spot things.