World Community Grid requires work sent to volunteers' computers to be returned within a set time limit. This is to ensure the overall project batches do not get delayed. At the same time this facilitates the participation of devices that are on only a few hours per day. E.g. home computers can process a project in the background whilst doing email, web browsing and other housekeeping chores. The principle is that every cycle counts and a work unit eventually does get completed. Frequent checkpoints will let these jobs resume very near to where they were shut down the previous time.
|Human Proteome Folding - Phase 2||10 days|
|Help Conquer Cancer||7 days|
|Help Fight Childhood Cancer||10 days|
'Type A' work units
'Type B' work units
'Type C' work units
|Help Cure Muscular Dystrophy - Phase 2||10 days|
|Clean Energy Project - Phase 2||10 days|
|Computing for Clean Water||10 days|
High priority tasks Edit
Rush jobs to make up for tasks missing deadlines are usually a fraction of the original task deadline, but are generally sent to those computers known to World Community Grid for quick, valid returns and high current uptime history. The deadline algorithm is:
- Take the original deadline time and divide by 3. For example, if the original deadline was 20 days, then the rush job deadline would be 6 days, 16 hours.
- Compute the estimated turnaround time for the job on the client. If this time is more than the value in #1 then use this value up to a maximum of twice #1.
A reliable host is one that:
- Returns tasks within 48 hours.
- Almost always returns valid results.
This measurement includes the impact of queue size because a larger queue size will lengthen the 'turnaround' time for a task and push the computer out of the 'reliable' metric.
Beta tasks Edit
Beta tasks have varying deadlines depending on criteria like pre-launch testing or bug resolution. Again they have short return time requirements and are only distributed to those volunteers that specifically elected to participate in the testing programs and usually have their computers on 24/7 with permanent internet connection.
The maximum cached amount of work by a BOINC client 10 days and can either be set in the My Grid → Device Manager → Device Profile → Profile of Choice → Custom Options → Cache, or in the versions 5.10 and higher of BOINC clients using the Advanced menu → Preferences → Network Usage → "Additional Buffer Days" option.
How BOINC manages deadlines Edit
BOINC does not run work in deadline order. Normally, BOINC schedules tasks in the order they were received. Rush jobs will show messages like "Running - High Priority" and others like "Waiting to Run" if paused or preempted during the general state of Earliest deadline first (EDF) by some referred to as panic state when the order of processing is strictly according to which jobs needs to be completed soonest, irrespective of project.
It is not recommended to exceed 8 days of work buffer if e.g. running the 10 day deadline sciences, alone or in a mix, simply because of potential outages, particularly if work is only returned periodically. Take computer down time and variability of buffered task run times into consideration! Secondly, do not fill up the buffer with brand new projects as they could have infant bugs in the new science software. An initial full size production could reveal those late ones and cause a client to process large volumes of work that might in fact be bad. WCG can remotely cancel that work when aware of a high failure rate, but only if the host is on-line and has a scheduled contact with the project servers.
For information on the number of copies circulated to arrive at proper quorum validation visit the FAQ: Minimum quorum & Initial Distribution of Work Units (Tasks)
Late tasks generally do not get credit granted unless completed and sent back before the Extra Copy is returned. If not in time they get marked as "Too Late" on the Result Status page and get zero credit!
Related topics Edit
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