According to powertop httpd is waking up the cpu one time per second while doing nothing: 7,6% ( 1,0) httpd : schedule_timeout (process_timeout) Doing an strace on the httpd root process I got this: [root@localhost ~]# strace -ttt -p 12021 Process 12021 attached - interrupt to quit 1191198615.761495 select(0, NULL, NULL, NULL, {0, 687000}) = 0 (Timeout) 1191198616.449068 waitpid(-1, 0xbf981958, WNOHANG|WSTOPPED) = 0 1191198616.449309 select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout) 1191198617.449049 waitpid(-1, 0xbf981958, WNOHANG|WSTOPPED) = 0 1191198617.449274 select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout) 1191198618.449057 waitpid(-1, 0xbf981958, WNOHANG|WSTOPPED) = 0 1191198618.449284 select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout) 1191198619.449008 waitpid(-1, 0xbf981958, WNOHANG|WSTOPPED) = 0 1191198619.449312 select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout) 1191198620.449053 waitpid(-1, 0xbf981958, WNOHANG|WSTOPPED) = 0 I don't really understand that log, what is it doing? is there any way to solve this??
It's not really possible to change this within the current architecture; the parent wakes up once per second to be able to dynamically respond to changes in load (e.g. all the children have become busy and more are needed).
Joe, that's fair enough, however, I'd like to know your thoughts about this, possibly stupid, idea: Increase the time to wakeup when there is no load in the server for some time, probably a few seconds after MinSpareServers have been reached and there is no increase in the load. The main goal behind this for me is to reduce the wake ups during nights where my web application is almost unused, during the day it's a very loaded application so the current behavior is not really a problem. It's just that it would be nice to save a few more watts during nights. Thanks for your help.