Long process PHP stops after several minutes

What is the reason for process to end? Here is the part from log_file when this happened..

2015-01-28 13:28:19.808 [INFO] [62.54.16.41:52122-0#APVH_mysecrets.omg] Connection idle time: 901 while in state: 5 watching for event: 25,close!
2015-01-28 13:28:19.808 [NOTICE] [62.54.16.41:52122-0#APVH_mysecrets.omg] Content len: 0, Request line: 'GET /book/proce.php HTTP/1.1'
2015-01-28 13:28:19.808 [INFO] [62.54.16.41:52122-0#APVH_mysecrets.omg] Cookie len: 287, __utma=180804770.1735794271.1422399099.1422446914.1423443528.7; __utmb=180845770.5.10.1422443528; __utmc=180804770; __utmt=1; __utmz=180804770.1422339099.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); __atuvc=145%7C4; __atuvs=54c8c408a6681274004; PHPSESSID=q2mptsiddiminjd1aesv961ob0
2015-01-28 13:28:19.808 [INFO] [62.54.16.41:52122-0#APVH_mysecrets.omg] HttpExtConnector state: 8, request body sent: 0, response body size: 0, response body sent:0, left in buffer: 0, attempts: 0.
2015-01-28 13:28:19.808 [INFO] [62.54.16.41:52122-0#APVH_mysecrets.omg] Lsapi connection state: 3, watching event: 25, respState: 1, m_iTotalPending:0, m_iPacketLeft:0, m_iCurRespHeader:4, req sent for 901 seconds,Total processing time: 901.
2015-01-28 13:28:19.808 [INFO] [62.54.16.41:52122-0#APVH_mysecrets.omg] abort request..., code: 4 
2015-01-28 13:28:19.808 [INFO] [62.54.16.41:52122-0#APVH_mysecrets.omg] Abort request processing by PID:795360, kill: 1, begin time: 901, sent time: 901, req processed: 3

it because of max_execution_time exceeded ,you should increase max_execution_time on your php.ini time,