LHC@home

Hi everybody;

I would be interested to know if there is any way to receive smaller tasks or some parameter to adjust the remaining time of the tasks. I have multiple computer and one of this have a remaining time around 4 hours and others around 1 day.

There is no way to receive smaller tasks.

If you want to receive fewer tasks (for less remaining time), then just reduce the size of the buffer in BOINC Computing preferences.
I use the default of 0.1 + 0.5 days.

If you want to receive fewer tasks (for less remaining time), then just reduce the size of the buffer in BOINC Computing preferences.
I use the default of 0.1 + 0.5 days.

Okey, thank you! I'll try to change this parameters.

If you want to receive fewer tasks (for less remaining time), then just reduce the size of the buffer in BOINC Computing preferences.
I use the default of 0.1 + 0.5 days.

Okey, thank you! I'll try to change this parameters.

That will get you fewer tasks but they will not be smaller tasks.
All ATLAS task consist of 200 events. There is no way to get ATLAS tasks that have less than 200 events. The time required to process the 200 varies and is not predictable.

If you want to receive fewer tasks (for less remaining time), then just reduce the size of the buffer in BOINC Computing preferences.
I use the default of 0.1 + 0.5 days.

Okey, thank you! I'll try to change this parameters.

That will get you fewer tasks but they will not be smaller tasks.
All ATLAS task consist of 200 events. There is no way to get ATLAS tasks that have less than 200 events. The time required to process the 200 varies and is not predictable.

Bronco is right, i tried yesterday and i had the same result. So i've been searching in BOINC documentation and i found a tag in app_config.xml file that maybe could work. The tag is <cmdline>--memory_size_mb N</cmdline>, i only try this tag with <cmdline>--nthreads 1</cmdline>, but worked fine, so i'll try with the other option. Somebody knows more options for <cmdline> tag?

Are you still looking for a method to get smaller tasks?
As bronco already explained, there is no method.

The only thing you can do is to change the basic settings (#cpus, RAM size) already given by the server.
This makes sense if the basic settings lead to computation errors or make your computer sluggish.
Otherwise it's recommended to leave them untouched.

Are you still looking for a method to get smaller tasks?
As bronco already explained, there is no method.

The only thing you can do is to change the basic settings (#cpus, RAM size) already given by the server.
This makes sense if the basic settings lead to computation errors or make your computer sluggish.
Otherwise it's recommended to leave them untouched.

Yes, but i only supposed that could works. Just as you say, i can change the Computing preference parameters.

Thanks for your time!

Your strategy seems to be to reduce the task run time by assigning more CPUs to tasks. That can work but only if the host has enough memory.
The following app_config.xml should work to run max 1 ATLAS vbox task at a time with 2 CPUs per task if the host has enough memory.
If it works then you could try 2 tasks concurrently by increasing the <max_concurrent> (not <project_max_concurrent>) value to 2.

The <project_max_concurrent> is commented out between <!-- and --> tags because it is optional.
Some of the other lines are optional too but I am not sure how those work. I think (maybe) <avg_ncpus> overrides the <cmdline>--nthreads</cmdline> which would mean you can eliminate the <cmdline>--nthreads</cmdline> if you include the <avg_ncpus>. Or maybe it's the opposite. If both lines are included then their values should match. As far as I know it does no harm to include both.

<app_config>
   <!-- <project_max_concurrent>4</project_max_concurrent> -->
   <app>
     <name>ATLAS</name>
     <max_concurrent>1</max_concurrent>
   </app>
   <app_version>
     <app_name>ATLAS</app_name>
     <plan_class>vbox64_mt_mcore_atlas</plan_class>
     <avg_ncpus>2</avg_ncpus>
     <cmdline>--nthreads 2 </cmdline>
     <!-- RAM formula: RAM = 3000 + 900 * ncpus -->
     <cmdline>--memory_size_mb 4800 </cmdline>
   </app_version>
</app_config>

Your strategy seems to be to reduce the task run time by assigning more CPUs to tasks. That can work but only if the host has enough memory.
The following app_config.xml should work to run max 1 ATLAS vbox task at a time with 2 CPUs per task if the host has enough memory.
If it works then you could try 2 tasks concurrently by increasing the <max_concurrent> (not <project_max_concurrent>) value to 2.

The <project_max_concurrent> is commented out between <!-- and --> tags because it is optional.
Some of the other lines are optional too but I am not sure how those work. I think (maybe) <avg_ncpus> overrides the <cmdline>--nthreads</cmdline> which would mean you can eliminate the <cmdline>--nthreads</cmdline> if you include the <avg_ncpus>. Or maybe it's the opposite. If both lines are included then their values should match. As far as I know it does no harm to include both.

<app_config>
   <!-- <project_max_concurrent>4</project_max_concurrent> -->
   <app>
     <name>ATLAS</name>
     <max_concurrent>1</max_concurrent>
   </app>
   <app_version>
     <app_name>ATLAS</app_name>
     <plan_class>vbox64_mt_mcore_atlas</plan_class>
     <avg_ncpus>2</avg_ncpus>
     <cmdline>--nthreads 2 </cmdline>
     <!-- RAM formula: RAM = 3000 + 900 * ncpus -->
     <cmdline>--memory_size_mb 4800 </cmdline>
   </app_version>
</app_config>

Thank you very much bronco;

I was reading the BOINC Client configuration documentation and i understood that <app> tag is the same that <app_name>, but for older BOINC versions. Finally, i have chosen to use ATLAS native app. Because i think that singularity could be better in performance than VirtualBox.
So now i have ATLAS native tasks with 2-4h of remaining time.