Contextual links - performance issue

[Gormartsen]

I just noticed that this module slow down Backdrop.

Some debug info: (it's a function call tree)

[2.5%]  |    |    |    |    |    |    └── theme [0.06 Mb] [realtime: 2.993 ms] 
[2.4%]  |    |    |    |    |    |    |    └── template_preprocess_block [0.06 Mb] [realtime: 2.828 ms] 
[2.1%]  |    |    |    |    |    |    |    |    └── contextual_pre_render_links [0.06 Mb] [realtime: 2.427 ms] 
[2.0%]  |    |    |    |    |    |    |    |    |    └── menu_contextual_links [0.06 Mb] [realtime: 2.350 ms] 
[1.5%]  |    |    |    |    |    |    |    |    |    |    └── menu_get_item [0.05 Mb] [realtime: 1.763 ms] 
[1.0%]  |    |    |    |    |    |    |    |    |    |    |    └── db_query_range [0.02 Mb] [realtime: 1.179 ms] 

The real problem is here:

https://github.com/backdrop/backdrop/blob/a5070a3ac1d5efb99bcae631b2b0b7484320f33e/core/includes/menu.inc#L2177

function menu_contextual_links($module, $parent_path, $args) {
......
  $router_item = menu_get_item($path);
  if (!$router_item || !$router_item['access']) {
    $path_empty[$parent_path] = TRUE;
    return $links;
  }

When I disable this module, page execution time decrease for ~10% for 6 blocks (like menu, breadcrumbs, footer and etc... you know, default one)

When I tested with 11 blocks, page execution time difference was 20%

• 150ms (contextual links enables)
• 118ms (disabled).

I don't have a solution for this issue so far.

[quicksketch]

Thanks for opening this @Gormartsen! I'm not sure what to do about this either quite yet. The Contextual Links module has always been implemented in a slightly obtuse fashion, but I believe it is built upon the menu system to accurately reflect the level of permissions for each item within the contextual menu.

What sort of servers are you doing your benchmarking? A 150ms response for an administrative user is still very good (IMO). Obviously Contextual Menus are permission-based, so none of these queries should get called for a less-privileged user and certainly not for anonymous pages.

[Gormartsen]

@quicksketch it's my MacBook Pro with SSD drive.
The main point to put this issue is that this module require up to 20% of total execution time. It's quite a lot for so small and simple idea.
From my point of view there is should be better solution to do the same, but I did not think about it.

I am finishing render cache module right now.
Will create PR soon ( I hope today).

Render cache will give us boost for 5 to 30% depends on page complexity.
It's smart cache - no issue with invalid cache.

[dboulet]

The Contextual Links module has always been implemented in a slightly obtuse fashion…

I preferred the way that this was originally implemented in the first version of Admin module in D6. When displaying an entity, block, or view, it would simply call hook_admin_link, providing contextual information to modules which were free to add links. Simple.

When the feature was ported to D7 core, it got tied in to the Menu system and was made much more complicated than it needed to be (IMHO).

[Gormartsen]

@dboulet 👍

[klonos]

...the technicalities behind this is beyond me, but if the 20% execution time thing is true, then perhaps have contextual links disabled by default out of the box. Even if it is ~150ms, still perceptually it would give the impression of faster page load times. Just my simple-minded idea. Feel free to shoot me down.

[klonos]

Adding the "needs usage metrics" tag to this one ...for when #285 is implemented.

This issue was filed on Dec 13, 2015. php 7.0.0 was released on Dec 3, and 7.0.1 on Dec 17. @Gormartsen do you remember if you have used php5 or php7 for those benchmarks back then?