I also don't have direct access to the server as well, so I'm mostly guessing. Having separate benchmarks for neon and VFP means there's a broad bimodal distribution for the benchmark results. Where the mean falls depends upon the mix of machines. In general the neon machines (being newer and faster) will report first and more often, so early on the PFC distribution will reflect the fast machines. Slower machines will be underweighted. So the work will be estimated to complete quickly, and some machines will time out. In SETI beta, it resolves itself in a few weeks. I can't guarantee that it will anywhere else.
We see this with every release of a GPU app. The real capabilities of graphics cards vary by orders of magnitude from the estimate and by more from each other. The fast cards report first and most every else hits days of timeouts. One possible fix so to increase the timeout limits for the first 10 workunits for a host_app_version, until host based estimates take over. On Mon, Jun 9, 2014 at 2:02 AM, Richard Haselgrove < [email protected]> wrote: > I think Eric Korpela would be the best person to answer that question, but > I suspect 'probably not': further investigation over the weekend suggests > that the circumstances may be SIMAP-specific. > > It appears that the Android Whetstone benchmark used in the BOINC client > has separate code paths for ARM, vfp, and NEON processors: a vfp or NEON > processor will report that it is significantly faster than a plain-vanilla > ARM. > > However, SIMAP have only deployed a single Android app, which I'm assuming > only uses ARM functions: devices with vfp or NEON SIMD vectorisation > available would run the non-optimised application much slower than BOINC > expects. > > At my suggestion, Thomas Rattei (SIMAP admistrator) increased the > rsc_fpops_bound multiplier to 10x on Sunday afternoon. I note that the > maximum runtime displayed on > http://boincsimap.org/boincsimap/server_status.php has already increased > from 11 hours to 14 hours since he did that. > > Thomas has told me "We've seen that [EXIT_TIME_LIMIT_EXCEEDED] a lot. > However, due to Samsung PowerSleep, we thought these are mainly "lazy" > users just not using their phone regularly for computing." He's going to > monitor how this progresses during the remainder of the current batch, and > I've asked him to keep us updated on his observations. > > > > >________________________________ > > From: David Anderson <[email protected]> > >To: [email protected] > >Sent: Monday, 9 June 2014, 3:48 > >Subject: Re: [boinc_dev] EXIT_TIME_LIMIT_EXCEEDED (sorry, yes me again, > but please read) > > > > > >Does this problem occur on SETI@home? > >-- David > > > >On 07-Jun-2014 2:51 AM, Richard Haselgrove wrote: > > > >> 2) Android runtime estimates > >> > >> The example here is from SIMAP. During a recent pause between batches, > I noticed > >> that some of my 'pending validation' tasks were being slow to clear: > >> http://boincsimap.org/boincsimap/results.php?hostid=349248 > >> > >> The clearest example is the third of those three workunits: > >> http://boincsimap.org/boincsimap/workunit.php?wuid=57169928 > >> > >> Four of the seven replications have failed with 'Error while > computing', and > >> every one of those four is an EXIT_TIME_LIMIT_EXCEEDED on an Android > device. > >> > >> Three of the four hosts have never returned a valid result (total > credit zero), > >> so they have never had a chance to establish an APR for use in runtime > >> estimation: runtime estimates and bounds must have been generated by > the server. > >> > >> It seems - from these results, and others I've found pending on other > machines - > >> that SIMAP tasks on Android are aborted with EXIT_TIME_LIMIT_EXCEEDED > after ~6 > >> hours elapsed. For the new batch released today, SIMAP are using a 3x > bound > >> (which may be a bit low under the circumstances): > >> > >> <rsc_fpops_est>13500000000000.000000</rsc_fpops_est> > >> <rsc_fpops_bound>40500000000000.000000</rsc_fpops_bound> > >> > >> so I deduce that the tasks when first issued had a runtime estimate of > ~2 hours. > >> > >> My own tasks, on a fast Intel i5 'Haswell' CPU (APR 7.34 GFLOPS), take > over half > >> an hour to complete: two hours for an ARM device sounds suspiciously > low. The > >> only one of my Android wingmates to have registered an APR > >> (http://boincsimap.org/boincsimap/host_app_versions.php?hostid=771033) > is showing > >> 1.69 GFLOPS, but I have no way of knowing whether that APR was > established before > >> or after the task in question errored out. > >> > >> From experience - borne out by current tests at Albert@Home, where > server logs > >> are helpfully exposed to the public - initial server estimates can be > hopelessly > >> over-optimistic. These two are for the same machine: > >> > >> 2014-06-04 20:28:09.8459 [PID=26529] [version] [AV#716] > (BRP4G-cuda32-nv301) > >> adjusting projected flops based on PFC avg: 2124.60G 2014-06-07 > 09:30:56.1506 > >> [PID=10808] [version] [AV#716] (BRP4G-cuda32-nv301) setting projected > flops based > >> on host elapsed time avg: 23.71G > >> > >> Since SIMAP have recently announced that they are leaving the BOINC > platform at > >> the end of the year (despite being an Android launch partner with > Samsung), I > >> doubt they'll want to put much effort into researching this issue. > >> > >> But if other projects experimenting with Android applications are > experiencing a > >> high task failure rate, they might like to check whether > EXIT_TIME_LIMIT_EXCEEDED > >> is a significant factor in those failures, and if so, consider the other > >> remediation approaches (apart from outliers, which isn't relevant in > this case) > >> that I suggested to Eric Mcintosh at LHC. > >> _______________________________________________ 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. > > _______________________________________________ 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.
