mprime process appears to not be running...

[starionhost]

I have been attempting to install mprime on some servers in our data center.

I have noticed that after starting mprime, on some of the machines, mprime is showing high CPU usage in top as expected. But on a couple of machines, mprime is not even shown as one of the running processes, and does not appear to be doing anything. Processors on the machines that don't seem to be running the mprime process are:

Intel Celeron J1800 @ 2.41GHz
Intel Celeron 2.40GHz
Intel Xeon L5420 @ 2.50GHz

I have reinstalled, quit and released, restarted and gone through the settings a half-dozen times, but am not seeing anything that would kickstart this thing into number crunching, or anything preventing it.

Thoughts?

BTW, my 12-core Mac Pro is cranking out work units ahead of schedule and is keeping my office warm without the benefit of any heaters. I haven't tried breaking out the marshmallows yet though...

[Dubslow]

What's the output of ./mprime -d?

[chalsall]

Originally Posted by starionhost

I have reinstalled, quit and released, restarted and gone through the settings a half-dozen times, but am not seeing anything that would kickstart this thing into number crunching, or anything preventing it.

In addition to Dubslow's suggestion... Are you by any chance launching mprime into the background and then exiting? E.g. "./mprime & ; exit".

If so, it's important to decouple the STDIN, STDOUT and STDERR from the console before existing. For example, "./mprime </dev/null >/dev/null 2>/dev/null & ; exit". Otherwise after a short while mprime will exit when it sees its file handles are broken.

[Mark Rose]

You can also use screen -L /path/to/log/file

[starionhost]

I will look at all the suggestions here later today, but it should be noted that on the machines that are working vs. the machines that are not, I did nothing different in the installation or startup of mprime.

[starionhost]

Originally Posted by Dubslow

What's the output of ./mprime -d?

[root@tubby prime95]# ./mprime -d
[Main thread Feb 23 23:08] Mersenne number primality test program version 28.7
[Main thread Feb 23 23:08] Optimizing for CPU architecture: AMD K8, L2 cache size: 1 MB
Another mprime is already running!

I am showing 100% idle on CPU usage and mprime is not shown in a top listing.

[Prime95]

If there is a "PID=" entry in prime.txt or local.txt, try removing it.

[starionhost]

Originally Posted by Prime95

If there is a "PID=" entry in prime.txt or local.txt, try removing it.

Commented out the "Pid=" entry from local.txt file. Entry did not appear in the prime.txt file.

No change. Correction. CPU is still showing 100% idle, but top is showing mprime at 199.7% CPU.

So, now I'm confused.

How do I start mprime correctly from the command line, then get my terminal session back and still leave mprime running? Is it ./mprime </dev/null >/dev/null 2>/dev/null & ; exit as someone described earlier, and if so, can you explain what this does? I'm still somewhat green about the command line...

[Dubslow]

How many cores does your computer have? What do you mean by "showing 100% idle" while simultaneously top shows mprime using two cores?

The command you posted (./mprime > /dev/null 2>&1 & or other variants) will indeed launch an mprime process that is independent of the terminal you start it from, and it may only be killed by running killall mprime (as opposed to, say, Ctrl+C being the standard way to kill interactive processes on the command line).

ps aux | grep mprime and killall mprime will be useful commands if you do indeed detach mprime from the terminal (which is what the last & means in the command above).

Perhaps a better way to run it, and the way I run it, is to use the screen command. That way you may run mprime independently of whatever terminal you're currently using, but you can watch its output and send commands to it (be it Ctrl+C or use of mprime's text menu) as you desire.

Simply speaking, run screen, which will launch a new virtual terminal/screen; run ./mprime -d (without any of the other fancy shell garbage) (being sure there's no other instances running, as usual), and watch it run; when you get bored of watching it, hit Ctrl+A followed by Ctrl+D to detach from the virtual terminal/screen; detaching will leave it running in the background. Then from any other terminal, at any time, you may run screen -r to reattach to the already-running screen when you want to check up on mprime.

[starionhost]

Originally Posted by Dubslow

How many cores does your computer have? What do you mean by "showing 100% idle" while simultaneously top shows mprime using two cores?

I have 2 cores. I am simply going by the webmin CPU usage information, but I am seeing now that what webmin says is different than what top says....so skipping that for a second and moving on...

Originally Posted by Dubslow

ps aux | grep mprime and killall mprime will be useful commands if you do indeed detach mprime from the terminal (which is what the last & means in the command above).

I can't seem to get mprime to quit. killall mprime and it still shows in top.

I think I understand the rest about using screen, but I need to restart mprime somehow as it does not appear to be doing anything according to top. It's at the bottom of the cpu usage list at 0.0%, maybe stopped or idle somehow?

[Xyzzy]

You might want to create a user for mprime rather than use the root account.