Re: Defunct Processes

Ej,
  I have something tangentially related for you.  Openmosix programs
work best when system calls are kept to a minimum.  File I/O, getting
the time, dropping privileges, malloc, etc are all 'expensive'
operations.   If you have file I/O, read/write as much as you can
into/from memory at one time and then do everything else in arrays or
memory structures.  

 I know of one program, ngspice, which kept file io to a minimum but
periodically checked the system time so it could track how long
something was taking.  We found this out by using strace.  We rewrote
the program and removed the time() calls and the program execution time
(during migration) was reduced, I'm not exaggerating,  by two orders of
magnitude.

Matt

On Wed, 2006-10-25 at 06:49 +0000, "ej magpayo"  wrote:
> I have a few questions about openmosix. I'm not sure if you will
> answer this email or not because I know you guys are very busy.
> Anyway, I just want to clear some things so here it goes, I am a Sysad
> working for Wolfpac Mobile Inc, I implemented openmosix on 4 IBM x336
> running on dual core(2) , OS Centos 3.7, 2.4.24 kernel,
> openMosix-2.4.24-2. My servers are currently running our Mobile apps
> which are mostly written on perl, C  and java scripts. The scripts
> only run on one server and then uses the other 3's resources but
> according to mmon, the openmosix kernel is not distributing the
> processes. One of the main problem here is that all the applications
> running on the server will suddenly become "defunct" processes and
> after a few days of uptime, then the server's system processes will
> become defunct as well. What plan of action should I take for this?
> Should I inform the our developers to review openmosix and make thier
> codes cluster-aware? I booted the server to the default kernel of
> Centos to avoid downtime for the meantime.
> 
> regards, 
> --
> E J  M A G P A Y O
> Sr. Technical Applications Systems Administrator
> Systems & Network Infrastructure
> WOLFPAC MOBILE, INC.
> http://www.wolfpac.net
> phone: +63-2-897-6756/63-2-899-3177
> mobile: +63-920-952-4695
> --------------------------------------------------------------------
> "Music is the answer.." -- Danny Tenaglia
> 


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