今天我注意到，当从我们的网络服务器发出请求时，速度相当慢。
我开始研究它，发现了大量 root 拥有的 apache 进程。
我不确定这实际上是导致事情变慢的原因，但无论如何，它看起来并不好。
问题是，我不知道从这里做什么？
如何找出为什么有这么多根进程？
有人可以推荐一组测试吗？我尝试过跟踪其中的一些，它们似乎正在做一些事情，但是 strace 的输出超出了我的范围。
root 30918 1.8 1.3 84284 52296 ? Ss 14:11 0:01 /usr/sbin/apache2 -k restart
root 30919 0.0 1.1 84420 45612 ? S 14:11 0:00 /usr/sbin/apache2 -k restart
root 30920 0.0 1.1 84420 45604 ? S 14:11 0:00 /usr/sbin/apache2 -k restart
root 30921 0.0 1.1 84420 45612 ? S 14:11 0:00 /usr/sbin/apache2 -k restart
root 30922 0.1 1.1 84420 45612 ? S 14:11 0:00 /usr/sbin/apache2 -k restart
root 30923 0.0 1.1 84420 45612 ? S 14:11 0:00 /usr/sbin/apache2 -k restart
www-data 30926 6.6 1.5 104964 61336 ? S 14:12 0:03 /usr/sbin/apache2 -k restart
root 30930 0.1 1.1 84420 45616 ? S 14:12 0:00 /usr/sbin/apache2 -k restart
root 30933 0.0 1.1 84420 45616 ? S 14:12 0:00 /usr/sbin/apache2 -k restart
root 30935 0.0 1.1 84420 45616 ? S 14:12 0:00 /usr/sbin/apache2 -k restart
root 30936 0.0 1.1 84420 45616 ? S 14:12 0:00 /usr/sbin/apache2 -k restart
root 30937 0.0 1.1 84420 45616 ? S 14:12 0:00 /usr/sbin/apache2 -k restart
root 30938 0.0 1.1 84420 45616 ? S 14:12 0:00 /usr/sbin/apache2 -k restart
root 30961 0.0 1.1 84420 45612 ? S 14:12 0:00 /usr/sbin/apache2 -k restart
root 30989 0.0 1.1 84420 45612 ? S 14:12 0:00 /usr/sbin/apache2 -k restart
root 30990 0.0 1.1 84420 45612 ? S 14:12 0:00 /usr/sbin/apache2 -k restart
root 31011 0.1 1.1 84420 45612 ? S 14:12 0:00 /usr/sbin/apache2 -k restart
root 31013 0.1 1.1 84420 45612 ? S 14:12 0:00 /usr/sbin/apache2 -k restart
root 31014 0.0 1.1 84420 45612 ? S 14:12 0:00 /usr/sbin/apache2 -k restart
www-data 31175 2.5 1.5 104168 60524 ? S 14:12 0:00 /usr/sbin/apache2 -k restart
www-data 31189 2.3 1.4 102360 58920 ? S 14:12 0:00 /usr/sbin/apache2 -k restart
www-data 31190 1.5 1.4 101904 58356 ? S 14:12 0:00 /usr/sbin/apache2 -k restart
www-data 31191 0.3 1.1 84556 46760 ? S 14:12 0:00 /usr/sbin/apache2 -k restart
www-data 31192 1.4 1.4 101916 58384 ? S 14:12 0:00 /usr/sbin/apache2 -k restart
www-data 31193 1.5 1.4 101916 58376 ? S 14:12 0:00 /usr/sbin/apache2 -k restart
root 31240 0.1 1.1 84420 45612 ? S 14:12 0:00 /usr/sbin/apache2 -k restart
这是其中一个进程的 strace 输出的示例。
--- SIGCHLD (Child exited) @ 0 (0) ---
read(6, 0xff87f6ef, 1) = -1 EAGAIN (Resource temporarily unavailable)
getuid32() = 0
close(17) = 0
gettimeofday({1354109303, 670988}, NULL) = 0
semop(5668864, {{0, -1, SEM_UNDO}}, 1) = 0
accept(4, {sa_family=AF_INET, sin_port=htons(48107), sin_addr=inet_addr("192.168.16.12")}, [16]) = 17
fcntl64(17, F_GETFD) = 0
fcntl64(17, F_SETFD, FD_CLOEXEC) = 0
semop(5668864, {{0, 1, SEM_UNDO}}, 1) = 0
clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0xf74a2768) = 1949
waitpid(1949, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0) = 1949
--- SIGCHLD (Child exited) @ 0 (0) ---
read(6, 0xff87f6ef, 1) = -1 EAGAIN (Resource temporarily unavailable)
getuid32() = 0
close(17) = 0
gettimeofday({1354109305, 724358}, NULL) = 0
semop(5668864, {{0, -1, SEM_UNDO}}, 1) = 0
accept(4, {sa_family=AF_INET, sin_port=htons(48132), sin_addr=inet_addr("192.168.16.12")}, [16]) = 17
fcntl64(17, F_GETFD) = 0
fcntl64(17, F_SETFD, FD_CLOEXEC) = 0
semop(5668864, {{0, 1, SEM_UNDO}}, 1) = 0
clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0xf74a2768) = 1974
waitpid(1974, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0) = 1974
--- SIGCHLD (Child exited) @ 0 (0) ---
我已经禁用了 mods-enabled 中的所有模块，除了 auth、env、siteenv 和 alias 等基本模块之外，并启动了服务器。在这种情况下，我仍然得到 6 个 root apache 进程和 1 个 www-data 拥有的 apache 进程。
我已确保所有模块都是最新的。
日志中没有明显的错误。
配置遵循；
ServerRoot "/etc/apache2"
LockFile /var/lock/apache2/accept.lock
PidFile ${APACHE_PID_FILE}
Timeout 300
KeepAlive On
MaxKeepAliveRequests 100
KeepAliveTimeout 15
<IfModule mpm_worker_module>
StartServers 2
MaxClients 150
MinSpareThreads 25
MaxSpareThreads 75
ThreadsPerChild 25
MaxRequestsPerChild 0
</IfModule>
User ${APACHE_RUN_USER}
Group ${APACHE_RUN_GROUP}
AccessFileName .htaccess
<Files ~ "^\.ht">
Order allow,deny
Deny from all
</Files>
DefaultType text/plain
HostnameLookups Off
ErrorLog /var/log/apache2/error.log
LogLevel warn
Include /etc/apache2/mods-enabled/*.load
Include /etc/apache2/mods-enabled/*.conf
Include /etc/apache2/httpd.conf
Include /etc/apache2/ports.conf
LogFormat "%v:%p %h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" vhost_combined
LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined
LogFormat "%h %l %u %t \"%r\" %>s %b" common
LogFormat "%{Referer}i -> %U" referer
LogFormat "%{User-agent}i" agent
CustomLog /var/log/apache2/other_vhosts_access.log vhost_combined
Include /etc/apache2/conf.d/
Include /etc/apache2/sites-enabled/
编译后的模块有：
编译成模块：
核心.c
mod_log_config.c
mod_logio.c
itk.c
http_core.c
mod_so.c
所以我现在只运行 mpm_worker 配置。
DEBUG UPDATER
When I restart apache, and ps, I get something like this;
root 26921 0.5 1.3 80008 52452 ? Ss 21:27 0:02 /usr/sbin/apache2 -k start
root 27114 0.0 1.1 80144 44804 ? S 21:34 0:00 /usr/sbin/apache2 -k start
root 27115 0.0 1.1 80144 44820 ? S 21:34 0:00 /usr/sbin/apache2 -k start
root 27116 0.0 1.1 80144 44804 ? S 21:34 0:00 /usr/sbin/apache2 -k start
root 27117 0.0 1.1 80144 44804 ? S 21:34 0:00 /usr/sbin/apache2 -k start
root 27119 0.0 1.1 80144 44804 ? S 21:34 0:00 /usr/sbin/apache2 -k start
如果我将 LogLevel 进行调试并重新启动，那么我会看到来自 mod_proxy 的这些消息
[Thu Nov 29 21:34:01 2012] [info] Server built: Sep 9 2012 21:17:36
[Thu Nov 29 21:34:01 2012] [debug] itk.c(1100): AcceptMutex: sysvsem (default: sysvsem)
[Thu Nov 29 21:34:01 2012] [debug] proxy_util.c(1818): proxy: grabbed scoreboard slot 0 in child 27115 for worker proxy:reverse
[Thu Nov 29 21:34:01 2012] [debug] proxy_util.c(1818): proxy: grabbed scoreboard slot 0 in child 27114 for worker proxy:reverse
[Thu Nov 29 21:34:01 2012] [debug] proxy_util.c(1934): proxy: initialized single connection worker 0 in child 27115 for (*)
[Thu Nov 29 21:34:01 2012] [debug] proxy_util.c(1837): proxy: worker proxy:reverse already initialized
[Thu Nov 29 21:34:01 2012] [debug] proxy_util.c(1934): proxy: initialized single connection worker 0 in child 27114 for (*)
[Thu Nov 29 21:34:01 2012] [debug] proxy_util.c(1818): proxy: grabbed scoreboard slot 0 in child 27117 for worker proxy:reverse
[Thu Nov 29 21:34:01 2012] [debug] proxy_util.c(1837): proxy: worker proxy:reverse already initialized
[Thu Nov 29 21:34:01 2012] [debug] proxy_util.c(1934): proxy: initialized single connection worker 0 in child 27117 for (*)
[Thu Nov 29 21:34:01 2012] [debug] proxy_util.c(1818): proxy: grabbed scoreboard slot 0 in child 27119 for worker proxy:reverse
[Thu Nov 29 21:34:01 2012] [debug] proxy_util.c(1837): proxy: worker proxy:reverse already initialized
[Thu Nov 29 21:34:01 2012] [debug] proxy_util.c(1934): proxy: initialized single connection worker 0 in child 27119 for (*)
[Thu Nov 29 21:34:01 2012] [debug] proxy_util.c(1818): proxy: grabbed scoreboard slot 0 in child 27116 for worker proxy:reverse
[Thu Nov 29 21:34:01 2012] [debug] proxy_util.c(1837): proxy: worker proxy:reverse already initialized
[Thu Nov 29 21:34:01 2012] [debug] proxy_util.c(1934): proxy: initialized single connection worker 0 in child 27116 for (*)
[Thu Nov 29 21:36:20 2012] [notice] SIGHUP received. Attempting to restart
注意 pid 匹配。但是，如果我禁用 mod_proxy，那么这些消息就会消失，但我仍然会启动相同数量的根进程，所以我相信这是一种症状而不是原因。
