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ATLAS application :
three 1-core tasks possible with 16GB RAM?
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Send message Joined: 18 Dec 15 Posts: 1686 Credit: 100,472,215 RAC: 104,143 |
Did anyone ever succeed in running three 1-core tasks on a system with 16GB RAM? I set my app_config.xml accordingly, but only 2 tasks are running concurrently. (I know that I could set the system to run one 3-core task. I was just curious) |
Send message Joined: 14 Jan 10 Posts: 1268 Credit: 8,421,800 RAC: 1,930 |
When you have BOINC allowed to use the most of your memory it should be possible. Maybe you did not set max CPU's to 1 to in your preferences. When that's higher, BOINC will reserve more memory for your ATLAS tasks and the 3rd one is waiting for memory. |
Send message Joined: 18 Dec 15 Posts: 1686 Credit: 100,472,215 RAC: 104,143 |
thanks, Crystal Pellet, for your reply. You are right, max CPUs was set higher than 1 in the preferences. I will correct this now and see what happens after new tasks will be downloaded with this new setting. BTW, can I see somewhere how much RAM BOINC is reserving for a given task? Obviously, that must be different (i.e. higher) to the 3.900MB that I have set in the app_config.xml. EDIT: I just changed the preferences to # of tasks: 3, and # of cores: 1 And by doing this, I seem to be caught in the known trap - this setting would let me download only 1 task, not 3 :-( |
Send message Joined: 14 Jan 10 Posts: 1268 Credit: 8,421,800 RAC: 1,930 |
BTW, can I see somewhere how much RAM BOINC is reserving for a given task? Obviously, that must be different (i.e. higher) to the 3.900MB that I have set in the app_config.xml.That's the same formula: 3000MB + ncpus*900MB. So when it was 8 or No Limit BOINC reserves 10200MB for 1 task not knowing what you configured in app_config. EDIT: I just changed the preferences to # of tasks: 3, and # of cores: 1AAAhh, the same old server bug. I don't understand that it can't be fixed. So when you would set 3 cores BOINC would reserve 5700MB and you would get 3 tasks, but 16GB is still too less. Only hanky panky helps here: Load a number of Atlas-tasks and don't let start them. Shutdown BOINC client and edit client_state.xml Change <rsc_memory_bound>xxxxxxxxxxxxxx</rsc_memory_bound> in the ATLAS workunits to a lower number. |
Send message Joined: 15 Jun 08 Posts: 2386 Credit: 223,024,012 RAC: 136,326 |
The project server calculates 2 memory values, both based on the well known RAM formula. memory_size_mb is used when a fresh VM is initialized. This value can be modified using an app_config.xml rsc_memory_bound is used by the BOINC client to decide if there's enough free RAM to start a task. This value can't be modified by the client. If at your web preferences #cores (per task) is set to unlimited or a high value and you run a 1-core setup it may result in a situation where the BOINC client thinks too much RAM is already in use. |
Send message Joined: 15 Jun 08 Posts: 2386 Credit: 223,024,012 RAC: 136,326 |
... the same old server bug. I don't understand that it can't be fixed. I agree. Very old, very nasty and it has been reported very often, e.g. by Erich. |
Send message Joined: 18 Dec 15 Posts: 1686 Credit: 100,472,215 RAC: 104,143 |
Only hanky panky helps here:okay, thanks for the hint. While 2 tasks are currently running (and I don't want to kill them) I took a look at the client_state.xml. It shows the following value: <rsc_memory_bound>5976883200.000000</rsc_memory_bound> I guess, for future tasks, changing this value to about 4 GB should work - do you people agree? |
Send message Joined: 14 Jan 10 Posts: 1268 Credit: 8,421,800 RAC: 1,930 |
I took a look at the client_state.xml. It shows the following value:Yes that's right. When the server would work well with the setting of 1 CPUs, the rsc_memory_bound in bytes would be 4089446400. When BOINC is allowed to use (almost) 100% of your memory, 3 ATLAS-tasks should be running. |
Send message Joined: 18 Dec 15 Posts: 1686 Credit: 100,472,215 RAC: 104,143 |
I followed the instructions given above (setting the value, to make is simple, to straight 4000000000.00000) and it works with 3 tasks simultaneously - all 3 of them startet right away. At this point, after about 1 1/2 hours, the total RAM usage is shown as 14.46GB. So I'll see how it develops during the following night (if I am unlucky, it will go up more and eventually crash; if I am lucky, the tasks will be finished tomorrow morning). Of course, the procedure of changing the rsc_memory_bound value is rather tedious :-( |
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