title: How to optimize the php process memory usage?
body: <p>I am running a wordpress site and each PHP process usage about 200mb to 250mb resident size memory. With 16GB of ram, the server can only handle about 70 processes. By increasing the virtual memory to 16GB it can handle 140. After that the load keeps rising. If there are 200 connections in 10 minutes, the server load reaches 20 on a 3Ghz quad-core xeon processor!</p>
  
  <p>I have tried deactivating all the plugins, but this only reduces the PHP memory usage of each process by less than 10%. suPHP tells me which user is using so much memory, but not what part of the wordpress code.</p>
  
  <p>Any suggestion on how to reduce the memory usage? Or is my only option to upgrade to 32GB of ram?</p>
  
  <pre><code>PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
  10585 nobody    16   0 2266m 237m 199m S 21.3  1.5   1:09.17 /usr/bin/php
  10597 nobody    16   0 2257m 255m 226m S 15.3  1.6   0:17.56 /usr/bin/php
  </code></pre>
  
  <p>Biggest outputs from pmap -d</p>
  
  <pre><code>000000000e8b8000   27580 rw--- 000000000e8b8000 000:00000   [ anon ]
  00002b3772850000 2097152 rw-s- 0000000000000000 000:00009   [ shmid=0x2d1b803a ]
  00002b37f2a62000   55108 r---- 0000000000000000 0fd:00000 locale-archive
  mapped: 2320852K    writeable/private: 30012K    shared: 2097152K
  </code></pre>
  
  <p>ipcs output</p>
  
  <pre><code>------ Semaphore Arrays --------
  
  key        semid      owner      perms      nsems
  0x000000a7 0          root      600        1
  0x00000000 162529281  nobody    600        1
  0x00000000 162562050  nobody    600        1
  0x00000000 162594819  nobody    600        1
  0x00000000 162627588  nobody    600        1
  ------ Message Queues --------
  
  key        msqid      owner      perms      used-bytes   messages`
  </code></pre>