too many processes

linus123 · 11-16-2004, 05:06 AM

hi guys,

there are tomcat4, mysql and a ftp-server running on my Debian-Server (Debian3.0 woody, kernel 2.2.2).

Typing ps aux results in

USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 1 0.0 0.2 1492 80 ? S Nov10 0:04 init [2]
root 2 0.0 0.0 0 0 ? SW Nov10 0:04 [kflushd]
root 3 0.0 0.0 0 0 ? SW Nov10 0:02 [kupdate]
root 4 0.0 0.0 0 0 ? SW Nov10 3:44 [kswapd]
root 5 0.0 0.0 0 0 ? SW Nov10 0:00 [keventd]
root 150 0.0 0.7 1540 224 ? S Nov10 0:00 /sbin/syslogd
root 153 0.0 0.0 1832 0 ? SW Nov10 0:00 [klogd]
root 168 0.0 0.6 2892 196 ? S Nov10 0:00 /usr/sbin/sshd
root 173 0.0 0.0 1488 0 tty1 SW Nov10 0:00 [getty]
root 174 0.0 0.0 1488 0 tty2 SW Nov10 0:00 [getty]
root 175 0.0 0.0 1488 0 tty3 SW Nov10 0:00 [getty]
root 176 0.0 0.0 1488 0 tty4 SW Nov10 0:00 [getty]
root 177 0.0 0.0 1488 0 tty5 SW Nov10 0:00 [getty]
root 178 0.0 0.0 1488 0 tty6 SW Nov10 0:00 [getty]
root 10609 0.0 0.0 2248 0 ? SW Nov12 0:00 [mysqld_safe]
mysql 10630 0.0 5.8 33436 1752 ? S Nov12 0:01 [mysqld]
mysql 10632 0.0 5.8 33436 1752 ? S Nov12 0:00 [mysqld]
mysql 10633 0.0 5.8 33436 1752 ? S Nov12 0:00 [mysqld]
mysql 10634 0.0 5.8 33436 1752 ? S Nov12 0:00 [mysqld]
mysql 10635 0.0 5.8 33436 1752 ? S Nov12 0:00 [mysqld]
mysql 10636 0.0 5.8 33436 1752 ? S Nov12 0:00 [mysqld]
mysql 10637 0.0 5.8 33436 1752 ? S Nov12 0:02 [mysqld]
mysql 10638 0.0 5.8 33436 1752 ? S Nov12 0:00 [mysqld]
mysql 10639 0.0 5.8 33436 1752 ? S Nov12 0:00 [mysqld]
mysql 10640 0.0 5.8 33436 1752 ? S Nov12 0:00 [mysqld]
root 11010 0.0 0.0 1484 0 ? SW Nov15 0:00 [inetd]
root 11019 0.0 0.0 1484 0 ? SW Nov15 0:00 [inetd]
root 11022 0.0 0.0 1484 0 ? SW Nov15 0:00 [inetd]
root 11024 0.0 0.0 1484 0 ? SW Nov15 0:00 [inetd]
root 11026 0.0 0.0 1484 0 ? SW Nov15 0:00 [inetd]
root 11079 0.0 0.0 1484 0 ? SW Nov15 0:00 [inetd]
root 11111 0.0 0.0 1484 0 ? SW Nov15 0:00 [inetd]
root 11131 0.0 0.0 1484 0 ? SW Nov15 0:00 [inetd]
root 11133 0.0 0.0 1484 0 ? SW Nov15 0:00 [inetd]
nobody 13003 0.0 0.4 3148 144 ? S Nov15 0:00 proftpd (acceptin
root 15453 0.0 61.6 238716 18424 ? S Nov15 0:43 [java]
root 15454 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15455 0.0 61.6 238716 18424 ? S Nov15 0:16 [java]
root 15456 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15457 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15458 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15459 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15460 0.0 61.6 238716 18424 ? S Nov15 0:09 [java]
root 15461 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15463 0.0 61.6 238716 18424 ? S Nov15 0:01 [java]
root 15464 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15465 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15473 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15474 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15475 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15476 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15477 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15478 0.0 61.6 238716 18424 ? S Nov15 0:02 [java]
root 15479 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15480 0.0 61.6 238716 18424 ? S Nov15 0:16 [java]
root 15481 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15482 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15483 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15484 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15485 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15486 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15487 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15488 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15489 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15490 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 15515 0.0 61.6 238716 18424 ? S Nov15 0:00 [java]
root 16208 0.0 5.0 5924 1524 ? S 11:28 0:00 /usr/sbin/sshd
otto 16210 0.0 5.4 5924 1620 ? S 11:28 0:00 /usr/sbin/sshd
otto 16211 0.0 4.2 2444 1284 ttyp1 S 11:28 0:00 -bash
otto 16218 0.0 4.0 3268 1224 ttyp1 R 11:45 0:00 ps aux

-----------------------------------------------------------------------------
pstree gives back:

init-+-6*[getty]
|-9*[inetd]
|-java---java---29*[java]
|-keventd
|-kflushd
|-klogd
|-kswapd
|-kupdate
|-mysqld_safe---mysqld---mysqld---8*[mysqld]
|-proftpd
|-sshd---sshd---sshd---bash---pstree
`-syslogd

----------------------------------------------------------------------------

Why are there so many java - and mysqld-processes? Are they only subprocesses?
thanks

rjlee · 11-16-2004, 05:30 AM

It depends what you mean by a subprocess.

Most newer Java interpreters will use system processes to implement threads rather than putting several threads into the same process, to get the benefits of the kernel's advanced process scheduling and thus make the threads work faster. Also note that Java programs use at least two threads, if they have a GUI.

Most daemons will spawn at least one process for each client; I suspect the default behaviour for mysqld is to spawn several processes at once, so that a client can connect straight away without first waiting for a process to be spawned. This kind of behaviour can usually be configured somewhere. (10 seems like a typical default number to spawn at once).

Hope that helps,

—Robert J. Lee