That is why my Tomcats spawn a pool of sh scripts to have them run a unix
command (ImageMagick, etc.)
Forking of a threaded process is very expensive on a loaded server. Unix has to
suspend all threads, than fork, do a lot of housekeeping and than resume all
threads. After making a pool of running sh instances which listen on stdin for
commands my system %cpu went down so it has more time for user %cpu. Throughput
doubled in my scenario's.
Ronald.
Op woensdag, 17 november 2010 22:30 schreef Leon Rosenberg
<rosenberg.l...@gmail.com>:
Hi,
I have a ugly issue I'm sure many people on this list already solved.
For multiple purposes I need pid's of processes, to stop/start them or
ensure they are running. So far nothing spectacular.
To obtain the pid I have following util:
String[] cmd = { "/bin/bash", "-c", "echo $PPID" };
p = Runtime.getRuntime().exec(cmd);
and afterwards read the ppid from the output stream of my process. So
far - so good.
The problem now occurs if a process has a lot of memory configured.
Like 25Gb on a 32Gb machine. In such a configuration the above command
fails with an OS'es out of memory, because fork
fails to create another process with THAT amount of memory:
1598388 2010-11-17 02:54:47,061 ERROR net.anotheria.util.PidTools -
Could not determine PID: java.io.IOException: Cannot run program
"/bin/bash": java.io.IOException: error=12, Cannot allocate memory
Is there another method to obtain the process id from within the process?
regards
Leon
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