help improving performance on a non-root process

[sombriks]

hello all

i have a java app server running under a non-root user, but i want to do some tweaks not related with java, but with the process itself.

see, this process uses great amounts of memory and open several files in the disk so it becomes quite slow. i also have a smaller app server (also java) and that one opens much less files and is much faster.

so, in order to enhance the process performance i've made a "renice -n -20 " as root and it makes a big difference.

now i would like to know how to allow my user running the server get allowed to open more files.

i've heard that there are some limits, bu i have no idea how to modify that.

thanks a lot in advance.

[Steven E. Protter · Accepted solution]

Shalom,

Note: Java itself can be a memory hog. Patching the system and going to later versions of JVM or JRE or JDK can have substantial performance boosts.

For your question, check the ulimit setting for this user.

You also might need to modify kernel parameters maxuprc to deal with limits on the number of processes a single user can have. The default of 75 can be a problem.

As far as renice goes, pushing much farther than you have gone with a lower renice figure might do more harm than good.

SEP

[Michael Steele_2]

Hi

Just a word of warning before I start researching your question; Renice / nice.

Nicing is an obsolete procedure by maybe two decades because it applies to a cpu bottleneck only, and cpu's no longer have the limitations that they once had.

And although still around nicing is determined by the O/S by default, where every process gets a defaulted job priority scheduled.

Worse case, your suped up nice processes take over the box preventing other processes from getting enough resources. In short, creating a dedicated box, or, a hung box that can't spawn a login shell because the login process doesn't have a high enough nice / priority.

[sombriks]

hey, thanks a lot for the answers!

i'll take care with nice (though the app server with -20 is at speedlight) and will check ulimit tonight.

[Kapil Jha]

you may also like to check kernel parameter
nfile,maxuprc and maxfiles.

BR,
Kapil+

[Emil Velez]

Do you have MCOE or DCOE on your system.

IF you do then you have PRM. WIth PRM you can cause proceses in a certain group defined by userid and process name to have more resources.

The PRM configuration would need to be created by root but once the configuration is created by virtue of the processes existing running with a certain userid or name it can be given higher resource priority.