In the last 24 hours, one of my rigs, with a single GPU, has on three occasions had another WU downloaded very soon after the current WU has started.

Network Usage is set to "Max additional work buffer" = 0.01 days, as it has been for years!!

Am I missing something??

It just did it again! 20% of the current WU done and another is downloading!!

What is the 'Minimum work buffer' set to?

What is the 'Minimum work buffer' set to?

0.00...

Max work buffer must be 0.00 as well.

If it predicts it will be out of work within 3 minutes, it will download more work, regardless of the min_buffer settings.
You can turn on the <work_fetch_debug> flag, to get more logging information, for you and for us to look at.
See http://boinc.berkeley.edu/wiki/Client_configuration

In the last 24 hours, one of my rigs, with a single GPU, has on three occasions had another WU downloaded very soon after the current WU has started.

Network Usage is set to "Max additional work buffer" = 0.01 days, as it has been for years!!

I saw that a day or two ago also, though which machine I don't remember (single or dual cards). But I keep a tight buffer too, though not quite that tight; usually about 0.10 days min, 0.05 days additional.

I saw that a day or two ago also, though which machine I don't remember (single or dual cards).

Which single cards are OK for GPUGrid?

You can turn on the <work_fetch_debug> flag, to get more logging information, for you and for us to look at.
See http://boinc.berkeley.edu/wiki/Client_configuration

Seems that flag is enabled by default, so I checked out the log around the time I got an unwanted WU.

There was a funny. Twice I got "This computer has reached a limit on tasks in progress" and the active WU restarted.

It was after the uploading WU was finished that I got the unwanted WU.

13/01/2014 14:21:16 | GPUGRID | Starting task 38x23-NOELIA_FXArep-0-2-RND0942_0 using acemdlong version 814 (cuda42) in slot 0
13/01/2014 14:21:29 | GPUGRID | Started upload of 31x-SANTI_MAR422cap310-19-32-RND2983_0_0
[removed other upload entries]
13/01/2014 14:35:40 | GPUGRID | Sending scheduler request: To fetch work.
13/01/2014 14:35:40 | GPUGRID | Requesting new tasks for NVIDIA
13/01/2014 14:35:43 | GPUGRID | Scheduler request completed: got 0 new tasks
13/01/2014 14:35:43 | GPUGRID | No tasks sent
13/01/2014 14:35:43 | GPUGRID | This computer has reached a limit on tasks in progress
13/01/2014 14:36:37 | GPUGRID | Restarting task 38x23-NOELIA_FXArep-0-2-RND0942_0 using acemdlong version 814 (cuda42) in slot 0
13/01/2014 14:40:08 | GPUGRID | Restarting task 38x23-NOELIA_FXArep-0-2-RND0942_0 using acemdlong version 814 (cuda42) in slot 0
13/01/2014 14:42:22 | GPUGRID | Restarting task 38x23-NOELIA_FXArep-0-2-RND0942_0 using acemdlong version 814 (cuda42) in slot 0
13/01/2014 14:48:09 | GPUGRID | Restarting task 38x23-NOELIA_FXArep-0-2-RND0942_0 using acemdlong version 814 (cuda42) in slot 0
13/01/2014 15:07:20 | GPUGRID | Sending scheduler request: To fetch work.
13/01/2014 15:07:20 | GPUGRID | Requesting new tasks for NVIDIA
13/01/2014 15:07:23 | GPUGRID | Scheduler request completed: got 0 new tasks
13/01/2014 15:07:23 | GPUGRID | No tasks sent
13/01/2014 15:07:23 | GPUGRID | This computer has reached a limit on tasks in progress
13/01/2014 15:08:20 | GPUGRID | Restarting task 38x23-NOELIA_FXArep-0-2-RND0942_0 using acemdlong version 814 (cuda42) in slot 0
13/01/2014 15:08:45 | GPUGRID | Finished upload of 31x-SANTI_MAR422cap310-19-32-RND2983_0_9
13/01/2014 15:08:49 | GPUGRID | Sending scheduler request: To report completed tasks.
13/01/2014 15:08:49 | GPUGRID | Reporting 1 completed tasks
13/01/2014 15:08:49 | GPUGRID | Not requesting tasks: don't need
13/01/2014 15:08:52 | GPUGRID | Scheduler request completed
13/01/2014 15:20:12 | GPUGRID | Sending scheduler request: To fetch work.
13/01/2014 15:20:12 | GPUGRID | Requesting new tasks for NVIDIA
13/01/2014 15:20:16 | GPUGRID | Scheduler request completed: got 1 new tasks

There was a funny.

I checked the other two unwanted WUs I got. The situation was the same; limit reached x 2 and unwanted WU arrived after the uploaded one finished.

The debug flag Jacob suggested is not on by default. The default logging gives the messages you see which are mostly just what the scheduler does but not why. If you turn on the flag Jacob suggested you will get additional messages that explain why the scheduler does what it does. The devil is in those details.

13/01/2014 14:36:37 | GPUGRID | Restarting task 38x23-NOELIA_FXArep-0-2-RND0942_0 using acemdlong version 814 (cuda42) in slot 0
13/01/2014 14:40:08 | GPUGRID | Restarting task 38x23-NOELIA_FXArep-0-2-RND0942_0 using acemdlong version 814 (cuda42) in slot 0
13/01/2014 14:42:22 | GPUGRID | Restarting task 38x23-NOELIA_FXArep-0-2-RND0942_0 using acemdlong version 814 (cuda42) in slot 0
13/01/2014 14:48:09 | GPUGRID | Restarting task 38x23-NOELIA_FXArep-0-2-RND0942_0 using acemdlong version 814 (cuda42) in slot 0
13/01/2014 15:07:20 | GPUGRID | Sending scheduler request: To fetch work.
13/01/2014 15:07:20 | GPUGRID | Requesting new tasks for NVIDIA
13/01/2014 15:07:23 | GPUGRID | Scheduler request completed: got 0 new tasks
13/01/2014 15:07:23 | GPUGRID | No tasks sent
13/01/2014 15:07:23 | GPUGRID | This computer has reached a limit on tasks in progress
13/01/2014 15:08:20 | GPUGRID | Restarting task 38x23-NOELIA_FXArep-0-2-RND0942_0 using acemdlong version 814 (cuda42) in slot 0
13/01/2014 15:08:45 | GPUGRID | Finished upload of 31x-SANTI_MAR422cap310-19-32-RND2983_0_9

The same task restarted 4X in 12 minutes, 5X in 24 minutes?

Edit added:

You have min. buffer = 0 and additional buffer = 0.1, IIUC. If you have min. buffer = 0 then you should also have additional buffer = 0. Or try min. buffer = 0.1 and additional buffer 0.

---

BOINC <<--- credit whores, pedants, alien hunters

I saw that a day or two ago also, though which machine I don't remember (single or dual cards).

Which single cards are OK for GPUGrid?

I use GTX 660s on both my machines (dual cards in one, single card in the other). I think it was very probably the single-card machine that had the problem, but I haven't seen it again. It was probably just a glitch in their server, though I may have been transferring cards between the machines around that time, and BOINC may have gotten confused as to which was which.

I saw that a day or two ago also, though which machine I don't remember (single or dual cards).

Which single cards are OK for GPUGrid?

I use GTX 660s on both my machines (dual cards in one, single card in the other). I think it was very probably the single-card machine that had the problem, but I haven't seen it again. It was probably just a glitch in their server, though I may have been transferring cards between the machines around that time, and BOINC may have gotten confused as to which was which.

I guess I should have ask "Who manufactures 660 singles?". I have two doubles in my rig but there's room for four singles!

tomba,

Jim is referring to a single quantity of cards, one card, not a single width card. You are misinterpreting his "single" to mean "single slot width".

---

BOINC <<--- credit whores, pedants, alien hunters

The debug flag Jacob suggested is not on by default. The default logging gives the messages you see which are mostly just what the scheduler does but not why. If you turn on the flag Jacob suggested you will get additional messages that explain why the scheduler does what it does. The devil is in those details.

OK. cc_config.xml updated.

The same task restarted 4X in 12 minutes, 5X in 24 minutes?

Yep. That's what the log tells us.

You have min. buffer = 0 and additional buffer = 0.1, IIUC. If you have min. buffer = 0 then you should also have additional buffer = 0. Or try min. buffer = 0.1 and additional buffer 0.

Both are now set to zero.

Just happened again, with cc_config.xml updated.

New WU downloaded at 12:01:24. Active WU will complete at 13:00.

15/01/2014 11:51:50 | | Starting BOINC client version 7.2.33 for windows_x86_64
15/01/2014 11:51:50 | | log flags: file_xfer, sched_ops, task, file_xfer_debug
15/01/2014 11:51:50 | | Libraries: libcurl/7.25.0 OpenSSL/1.0.1 zlib/1.2.6
15/01/2014 11:51:50 | | Data directory: C:\ProgramData\BOINC
15/01/2014 11:51:50 | | Running under account TOMBA
15/01/2014 11:51:50 | | CUDA: NVIDIA GPU 0: GeForce GTX 660 (driver version 331.93, CUDA version 6.0, compute capability 3.0, 2048MB, 1962MB available, 1982 GFLOPS peak)
15/01/2014 11:51:50 | | OpenCL: NVIDIA GPU 0: GeForce GTX 660 (driver version 331.93, device version OpenCL 1.1 CUDA, 2048MB, 1962MB available, 1982 GFLOPS peak)
15/01/2014 11:51:50 | | Host name: XPS-435
15/01/2014 11:51:50 | | Processor: 8 GenuineIntel Intel(R) Core(TM) i7 CPU 920 @ 2.67GHz [Family 6 Model 26 Stepping 5]
15/01/2014 11:51:50 | | Processor features: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss htt tm pni ssse3 cx16 sse4_1 sse4_2 popcnt syscall nx lm vmx tm2 pbe
15/01/2014 11:51:50 | | OS: Microsoft Windows 7: Home Premium x64 Edition, Service Pack 1, (06.01.7601.00)
15/01/2014 11:51:50 | | Memory: 5.99 GB physical, 11.98 GB virtual
15/01/2014 11:51:50 | | Disk: 465.76 GB total, 374.30 GB free
15/01/2014 11:51:50 | | Local time is UTC +1 hours
15/01/2014 11:51:50 | | VirtualBox version: 4.3.4
15/01/2014 11:51:50 | | Config: use all coprocessors
15/01/2014 11:51:50 | GPUGRID | URL http://www.gpugrid.net/; Computer ID 157241; resource share 100
15/01/2014 11:51:50 | GPUGRID | General prefs: from GPUGRID (last modified 27-Aug-2013 13:11:17)
15/01/2014 11:51:50 | GPUGRID | Computer location: home
15/01/2014 11:51:50 | GPUGRID | General prefs: no separate prefs for home; using your defaults
15/01/2014 11:51:50 | | Reading preferences override file
15/01/2014 11:51:50 | | Preferences:
15/01/2014 11:51:50 | | max memory usage when active: 6134.97MB
15/01/2014 11:51:50 | | max memory usage when idle: 6134.97MB
15/01/2014 11:51:50 | | max disk usage: 232.88GB
15/01/2014 11:51:50 | | max CPUs used: 3
15/01/2014 11:51:50 | | max download rate: 2048000 bytes/sec
15/01/2014 11:51:50 | | max upload rate: 135004 bytes/sec
15/01/2014 11:51:50 | | (to change preferences, visit a project web site or select Preferences in the Manager)
15/01/2014 11:51:50 | | Not using a proxy
15/01/2014 11:51:55 | GPUGRID | project resumed by user
15/01/2014 11:51:56 | GPUGRID | Restarting task 39x756-NOELIA_FXArep-0-2-RND3960_0 using acemdlong version 814 (cuda55) in slot 0
15/01/2014 12:01:21 | GPUGRID | Sending scheduler request: To fetch work.
15/01/2014 12:01:21 | GPUGRID | Requesting new tasks for NVIDIA
15/01/2014 12:01:24 | GPUGRID | Scheduler request completed: got 1 new tasks
15/01/2014 12:01:26 | GPUGRID | Started download of 22x-SANTI_MAR419cap310-28-LICENSE
15/01/2014 12:01:26 | GPUGRID | [file_xfer] URL: http://www.gpugrid.org/PS3GRID/download/1c0/22x-SANTI_MAR419cap310-28-LICENSE
15/01/2014 12:01:26 | GPUGRID | Started download of 22x-SANTI_MAR419cap310-28-COPYRIGHT
15/01/2014 12:01:26 | GPUGRID | [file_xfer] URL: http://www.gpugrid.org/PS3GRID/download/230/22x-SANTI_MAR419cap310-28-COPYRIGHT
15/01/2014 12:01:28 | GPUGRID | [file_xfer] http op done; retval 0 (Success)
15/01/2014 12:01:28 | GPUGRID | [file_xfer] http op done; retval 0 (Success)
15/01/2014 12:01:28 | GPUGRID | [file_xfer] file transfer status 0 (Success)
15/01/2014 12:01:28 | GPUGRID | Finished download of 22x-SANTI_MAR419cap310-28-LICENSE
15/01/2014 12:01:28 | GPUGRID | [file_xfer] Throughput 9572 bytes/sec
15/01/2014 12:01:28 | GPUGRID | [file_xfer] file transfer status 0 (Success)
15/01/2014 12:01:28 | GPUGRID | Finished download of 22x-SANTI_MAR419cap310-28-COPYRIGHT
15/01/2014 12:01:28 | GPUGRID | [file_xfer] Throughput 1583 bytes/sec
15/01/2014 12:01:28 | GPUGRID | Started download of 22x-SANTI_MAR419cap310-28-22x-SANTI_MAR419cap310-27-32-RND3945_1
15/01/2014 12:01:28 | GPUGRID | [file_xfer] URL: http://www.gpugrid.org/PS3GRID/download/19f/22x-SANTI_MAR419cap310-28-22x-SANTI_MAR419cap310-27-32-RND3945_1
15/01/2014 12:01:28 | GPUGRID | Started download of 22x-SANTI_MAR419cap310-28-22x-SANTI_MAR419cap310-27-32-RND3945_2
15/01/2014 12:01:28 | GPUGRID | [file_xfer] URL: http://www.gpugrid.org/PS3GRID/download/388/22x-SANTI_MAR419cap310-28-22x-SANTI_MAR419cap310-27-32-RND3945_2
15/01/2014 12:01:33 | GPUGRID | [file_xfer] http op done; retval 0 (Success)
15/01/2014 12:01:33 | GPUGRID | [file_xfer] file transfer status 0 (Success)
15/01/2014 12:01:33 | GPUGRID | Finished download of 22x-SANTI_MAR419cap310-28-22x-SANTI_MAR419cap310-27-32-RND3945_2
15/01/2014 12:01:33 | GPUGRID | [file_xfer] Throughput 130346 bytes/sec
15/01/2014 12:01:33 | GPUGRID | Started download of 22x-SANTI_MAR419cap310-28-22x-SANTI_MAR419cap310-27-32-RND3945_3
15/01/2014 12:01:33 | GPUGRID | [file_xfer] URL: http://www.gpugrid.org/PS3GRID/download/81/22x-SANTI_MAR419cap310-28-22x-SANTI_MAR419cap310-27-32-RND3945_3
15/01/2014 12:01:38 | GPUGRID | [file_xfer] http op done; retval 0 (Success)
15/01/2014 12:01:38 | GPUGRID | [file_xfer] file transfer status 0 (Success)
15/01/2014 12:01:38 | GPUGRID | Finished download of 22x-SANTI_MAR419cap310-28-22x-SANTI_MAR419cap310-27-32-RND3945_3
15/01/2014 12:01:38 | GPUGRID | [file_xfer] Throughput 93616 bytes/sec
15/01/2014 12:01:38 | GPUGRID | Started download of 22x-SANTI_MAR419cap310-28-pdb_file
15/01/2014 12:01:38 | GPUGRID | [file_xfer] URL: http://www.gpugrid.org/PS3GRID/download/103/22x-SANTI_MAR419cap310-28-pdb_file
15/01/2014 12:01:42 | GPUGRID | [file_xfer] http op done; retval 0 (Success)
15/01/2014 12:01:42 | GPUGRID | [file_xfer] file transfer status 0 (Success)
15/01/2014 12:01:42 | GPUGRID | Finished download of 22x-SANTI_MAR419cap310-28-22x-SANTI_MAR419cap310-27-32-RND3945_1
15/01/2014 12:01:42 | GPUGRID | [file_xfer] Throughput 48728 bytes/sec
15/01/2014 12:01:42 | GPUGRID | Started download of 22x-SANTI_MAR419cap310-28-psf_file
15/01/2014 12:01:42 | GPUGRID | [file_xfer] URL: http://www.gpugrid.org/PS3GRID/download/136/22x-SANTI_MAR419cap310-28-psf_file
15/01/2014 12:02:01 | GPUGRID | [file_xfer] http op done; retval 0 (Success)
15/01/2014 12:02:01 | GPUGRID | [file_xfer] file transfer status 0 (Success)
15/01/2014 12:02:01 | GPUGRID | Finished download of 22x-SANTI_MAR419cap310-28-pdb_file
15/01/2014 12:02:01 | GPUGRID | [file_xfer] Throughput 100795 bytes/sec
15/01/2014 12:02:01 | GPUGRID | Started download of 22x-SANTI_MAR419cap310-28-par_file
15/01/2014 12:02:01 | GPUGRID | [file_xfer] URL: http://www.gpugrid.org/PS3GRID/download/26d/22x-SANTI_MAR419cap310-28-par_file
15/01/2014 12:02:07 | GPUGRID | Restarting task 39x756-NOELIA_FXArep-0-2-RND3960_0 using acemdlong version 814 (cuda55) in slot 0
15/01/2014 12:02:08 | GPUGRID | [file_xfer] http op done; retval 0 (Success)
15/01/2014 12:02:08 | GPUGRID | [file_xfer] file transfer status 0 (Success)
15/01/2014 12:02:08 | GPUGRID | Finished download of 22x-SANTI_MAR419cap310-28-psf_file
15/01/2014 12:02:08 | GPUGRID | [file_xfer] Throughput 179525 bytes/sec
15/01/2014 12:02:08 | GPUGRID | Started download of 22x-SANTI_MAR419cap310-28-conf_file_enc
15/01/2014 12:02:08 | GPUGRID | [file_xfer] URL: http://www.gpugrid.org/PS3GRID/download/3c4/22x-SANTI_MAR419cap310-28-conf_file_enc
15/01/2014 12:02:09 | GPUGRID | [file_xfer] http op done; retval 0 (Success)
15/01/2014 12:02:09 | GPUGRID | [file_xfer] file transfer status 0 (Success)
15/01/2014 12:02:09 | GPUGRID | Finished download of 22x-SANTI_MAR419cap310-28-conf_file_enc
15/01/2014 12:02:09 | GPUGRID | [file_xfer] Throughput 2754 bytes/sec
15/01/2014 12:02:09 | GPUGRID | Started download of 22x-SANTI_MAR419cap310-28-metainp_file
15/01/2014 12:02:09 | GPUGRID | [file_xfer] URL: http://www.gpugrid.org/PS3GRID/download/183/22x-SANTI_MAR419cap310-28-metainp_file
15/01/2014 12:02:10 | GPUGRID | [file_xfer] http op done; retval 0 (Success)
15/01/2014 12:02:10 | GPUGRID | [file_xfer] file transfer status 0 (Success)
15/01/2014 12:02:10 | GPUGRID | Finished download of 22x-SANTI_MAR419cap310-28-metainp_file
15/01/2014 12:02:10 | GPUGRID | [file_xfer] Throughput 166 bytes/sec
15/01/2014 12:02:10 | GPUGRID | Started download of 22x-SANTI_MAR419cap310-28-22x-SANTI_MAR419cap310-27-32-RND3945_7
15/01/2014 12:02:10 | GPUGRID | [file_xfer] URL: http://www.gpugrid.org/PS3GRID/download/2cd/22x-SANTI_MAR419cap310-28-22x-SANTI_MAR419cap310-27-32-RND3945_7
15/01/2014 12:02:11 | GPUGRID | [file_xfer] http op done; retval 0 (Success)
15/01/2014 12:02:11 | GPUGRID | [file_xfer] http op done; retval 0 (Success)
15/01/2014 12:02:11 | GPUGRID | [file_xfer] file transfer status 0 (Success)
15/01/2014 12:02:11 | GPUGRID | Finished download of 22x-SANTI_MAR419cap310-28-par_file
15/01/2014 12:02:11 | GPUGRID | [file_xfer] Throughput 75904 bytes/sec
15/01/2014 12:02:11 | GPUGRID | [file_xfer] file transfer status 0 (Success)
15/01/2014 12:02:11 | GPUGRID | Finished download of 22x-SANTI_MAR419cap310-28-22x-SANTI_MAR419cap310-27-32-RND3945_7
15/01/2014 12:02:11 | GPUGRID | [file_xfer] Throughput 0 bytes/sec
15/01/2014 12:02:11 | GPUGRID | Started download of 22x-SANTI_MAR419cap310-28-22x-SANTI_MAR419cap310-27-32-RND3945_10
15/01/2014 12:02:11 | GPUGRID | [file_xfer] URL: http://www.gpugrid.org/PS3GRID/download/13e/22x-SANTI_MAR419cap310-28-22x-SANTI_MAR419cap310-27-32-RND3945_10
15/01/2014 12:02:12 | GPUGRID | [file_xfer] http op done; retval 0 (Success)
15/01/2014 12:02:12 | GPUGRID | [file_xfer] file transfer status 0 (Success)
15/01/2014 12:02:12 | GPUGRID | Finished download of 22x-SANTI_MAR419cap310-28-22x-SANTI_MAR419cap310-27-32-RND3945_10
15/01/2014 12:02:12 | GPUGRID | [file_xfer] Throughput 211 bytes/sec

tomba,

Jim is referring to a single quantity of cards, one card, not a single width card. You are misinterpreting his "single" to mean "single slot width".

Oops... Thanks for the heads-up!

Just happened again, with cc_config.xml updated.

New WU downloaded at 12:01:24. Active WU will complete at 13:00.

15/01/2014 11:51:50 | | Starting BOINC client version 7.2.33 for windows_x86_64
15/01/2014 11:51:50 | | log flags: file_xfer, sched_ops, task, file_xfer_debug
15/01/2014 11:51:50 | | Libraries: libcurl/7.25.0 OpenSSL/1.0.1 zlib/1.2.6

The red line lists the logging flags currently turned on. It looks like you turned on the <file_xfer_debug> instead of <work_fetch_debug>.

I'll turn you back over to Jacob for help interpreting the info <work_fetch_debug> will spit out. It's Greek to me.

---

BOINC <<--- credit whores, pedants, alien hunters

Once I can see work_fetch_debug output, I might be able to diagnose the situation, as I am quite familiar with it. I even worked with David to improve work fetch (and work_fetch_debug output) in the most recent release of BOINC.

Still waiting for work_fetch_debug output.

Matt Harvey quite recently implemented a technique called 'boinc_temporary_exit' to try and reduce the number of total task failures (that was app version 8.14). If things start to go a bit wobbly with a task, GPUGrid tells it to stop, take a deep breath, and try again later.

By 'take a deep breath', I mean that GPUGrid tells BOINC not to re-run the same task immediately, but to wait at least a few seconds - I don't know how long: you would have to enable yet another logging flag - 'task_debug' - in cc_config to see that.

If tasks are exiting so frequently, and if you don't carry a spare at all times, that would explain the early WU downloads:

task exits
task is waiting before it can run again
BOINC has nothing to do
BOINC requests new task
GPUGrid allocates new task
BOINC starts downloading files
scheduling delay on original task expires
original task is re-started

or something like that. In order to solve the 'early download' problem, you first have to find the cause of the temporary exits. It'll be a mild form of the 'GPUGrid stresses your GPU harder than anything else' issue that we've been discussing in the SANTI thread.