Understood. If the vast majority of projects wouldn't be able to checkpoint prior to suspending, it doesn't make sense to add a mechanism that only a few projects would use when resources could be better utilized on changes/enhancements that most/all can use. Since Collatz can, I'll just call its write_checkpoint function when BOINC is suspending. It might still be a nice tip to add to the wiki though. E.g. "If there is a long running workunit and the application can checkpoint when BOINC suspends it without causing a long delay, it should do so."
Jon Sonntag > -----Original Message----- > From: [email protected] [mailto:boinc_dev- > [email protected]] On Behalf Of David Anderson > Sent: Monday, July 16, 2012 3:55 PM > To: [email protected] > Subject: Re: [boinc_dev] [boinc_alpha] Tasks resume with same fraction > done > > Many (most?) applications can checkpoint only at specific moments (e.g. > completion of an outer loop) that may occur only every few minutes. > > When a job is ready to be preempted because of time-slicing, the scheduler > waits until it checkpoints. > So that's not an issue. > > The other cases are preempting because the user suspended activity, the > client is exiting, or the system is hibernating. > We could add a mechanism to request apps to checkpoint then, but it would > benefit only those apps that can checkpoint at any time. > > -- David > > On 16-Jul-2012 12:45 PM, Jon Sonntag wrote: > > Shouldn't time_to_checkpoint return true prior to BOINC suspending the > task? > > Then, only after checkpoint_completed is set, actually suspend the task? > > Or, is it up to the application to do a checkpoint by checking the > > boinc_status and doing a checkpoint even it not asked to do so when > BOINC is > > suspending the task? Otherwise, a couple minutes of work would be lost > on > > average every time it suspends. (5 minutes per checkpoint and > > switching between 2 projects every hour = 2.5 minutes lost on average. > > For long tasks, that could add up to a lot of time.) If it is the > > developers job to checkpoint on suspend, I would suggest adding that > > code to the sample apps as startup projects often use the uppercase > > sample apps as a template for their own code. > > > > Note: This topic started on BOINC_ALPHA, but I felt BOINC_DEV was a > > more appropriate place to get more clarification and/or expand the > discussion. > > > > Jon Sonntag > > [email protected] > > > >> -----Original Message----- > >> From: [email protected] [mailto:boinc_alpha- > >> [email protected]] On Behalf Of David Anderson > >> Sent: Monday, July 16, 2012 2:28 PM > >> To: [email protected] > >> Subject: Re: [boinc_alpha] Tasks resume with same fraction done > >> > >> Tasks resume from wherever they last checkpointed. > >> This is true whether you install a new version, or simply stop/start > >> the > > client. > >> -- David > >> > >> On 16-Jul-2012 7:21 AM, Jan Pillár wrote: > >>> Hi, > >>> > >>> > >>> I have a question about installing new version of BOINC over older > >>> one > >>> - tasks should resume with same fraction done. Should the tasks > >>> start with exactly the same fraction done or is there an acceptable > tolerance? > >>> > >>> For example, before installation of new version my tasks were at 34 > >>> %, after installation they were at 31 %. Is that OK? Does it have > >>> anything to do with "Task checkpoint to disk" settings? > >>> > >>> Kind Regards, > >>> > >>> Jan _______________________________________________ > >> boinc_alpha > >>> mailing list [email protected] > >>> http://lists.ssl.berkeley.edu/mailman/listinfo/boinc_alpha To > >>> unsubscribe, visit the above URL and (near bottom of page) enter > >>> your > >> email address. > >>> > >> > >> _______________________________________________ > >> boinc_alpha mailing list > >> [email protected] > >> http://lists.ssl.berkeley.edu/mailman/listinfo/boinc_alpha > >> To unsubscribe, visit the above URL and (near bottom of page) enter > >> your email address. > > > > _______________________________________________ > > boinc_dev mailing list > > [email protected] > > http://lists.ssl.berkeley.edu/mailman/listinfo/boinc_dev > > To unsubscribe, visit the above URL and (near bottom of page) enter > > your email address. > > > > _______________________________________________ > boinc_dev mailing list > [email protected] > http://lists.ssl.berkeley.edu/mailman/listinfo/boinc_dev > To unsubscribe, visit the above URL and > (near bottom of page) enter your email address. _______________________________________________ boinc_dev mailing list [email protected] http://lists.ssl.berkeley.edu/mailman/listinfo/boinc_dev To unsubscribe, visit the above URL and (near bottom of page) enter your email address.
