# [PATCH] fpm/feature: apache_like or dynamic spawning (for testing)

- Thread: https://externals.io/message/46409
- Original archive: https://news-web.php.net/php.internals/46409
- Started by jerome@loyet.net on 2009-12-13T19:06:04+00:00
- Messages: 1
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## #46409 — jerome@loyet.net — 2009-12-13T19:06:04+00:00

URL: https://externals.io/message/46409#46409

Hi all,

I spent some time working on the missing apache_like feature in FPM.

The attached patch is the first version and is for testing.

Changes:
1- rename apache_like to dynamic (in conf file and in source file)
2- add the dynamic spawning algorithm

The algorithm is based on the mod_worker from apache httpd

Algorihtm:

check start_servers, min_spare_servers, max_spare_servers
if start_server is not set, set it to (min_spare + (max_spare - min_spare) / 2)
for each pool, set a variable spawn_rate to 1
set a 1s timer event to perform idle server maintenance
each second
  for each pool {
    calculate nb_idle, number of idle process (based on
child->time_accepted which is set when a child accept() call returns
and reset when it call accept())
    if idle > max_spare {
      kill the oldest idle child
      set spawn_rate to 1
      continue to next pool
    }
    if idle < min_spare {
      set nb_children to MIN(spawn_rate, (min_spare - nb_idle))
      create nb_children
      if (spawn_rate < 32) {
        spawn_rate * 2
      }
      continue to next next pool
    }
    // nothing has been done (no fork and no kill)
    reset spawn_rate to 1
    continue to next pool
  }

spawn_rate is used to increase the number of child to create when
there is a lot of children to create at once. The first iteration it
will create 1, then 2, then 4, then 8, then 16.

I didn't do anything about handling the gracefull restart. I'll check
that later.

You can test it and make me returns.

Hope it helps
++ Jerome