Hang in there, Matt. Thanks for the prompt response, for keeping us informed, and for moving forward with the apps. Much respect.

I put the 335.23 driver on my Win7-64 machine, and it is now crunching the 8.40 Cuda55 tasks. They are short and not long, but now crunching and not getting errors. Will leave this driver on for a while. I had a soft spot for the 331.82 driver. Was able to get the better utilization with 331.82 according to Precision as compared to the 335.23.

Remember SWAN_SYNC? Next time I rev the app, I'll introduce the ability to force busy waiting, which ought to give best performance, at the cost of CPU.

Matt

Remember SWAN_SYNC? Next time I rev the app, I'll introduce the ability to force busy waiting, which ought to give best performance, at the cost of CPU.

All thumbs up for providing it as an option, for those who really want or need it!

MrS

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Remember SWAN_SYNC? Next time I rev the app, I'll introduce the ability to force busy waiting, which ought to give best performance, at the cost of CPU.

In the other thread you said 8.41 would already have it. I have such a CUDA 6 WU running under Win 8.1. I created a user or system environment variable called SWAN_SYNC, set it to 0 and rebooted. However, CPU usage remains at 1.4 - 1.8% (8 threads), so it's obviously not working yet. Did I do anything wrong?

MrS

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Scanning for our furry friends since Jan 2002

Try setting SWAN_SYNC to 1.
I can't test that yet because I'm running two 8.40 WU's. Maybe tomorrow I'll get some 8.41 WU's...

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Remember SWAN_SYNC? Next time I rev the app, I'll introduce the ability to force busy waiting, which ought to give best performance, at the cost of CPU.

In the other thread you said 8.41 would already have it. I have such a CUDA 6 WU running under Win 8.1. I created a user or system environment variable called SWAN_SYNC, set it to 0 and rebooted. However, CPU usage remains at 1.4 - 1.8% (8 threads), so it's obviously not working yet. Did I do anything wrong?

MrS

How can we do that set the environment variable for SWAN_SYNC? If that helps performance I might try updating to latest beta driver and see how the 780Ti will perform then.

Edit: Sorry for spamming, I found it here: http://www.gpugrid.net/forum_thread.php?id=2123&nowrap=true#16463
Did a search in the forum, but did not find, did a search in Google and there is the answer.

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Remember SWAN_SYNC? Next time I rev the app, I'll introduce the ability to force busy waiting, which ought to give best performance, at the cost of CPU.

In the other thread you said 8.41 would already have it. I have such a CUDA 6 WU running under Win 8.1. I created a user or system environment variable called SWAN_SYNC, set it to 0 and rebooted. However, CPU usage remains at 1.4 - 1.8% (8 threads), so it's obviously not working yet. Did I do anything wrong?

MrS

It is working for me, sort of, on my GTX 660 Ti, using the 8.41 cuda60 app. But it seems it is bugged - read on.

Note: You don't have to restart Windows in order to make this work. I'm using Process Explorer to monitor the CPU usage.

- If I close BOINC, go to Control Panel -> System -> Advanced -> Environment Variables, set a System variable SWAN_SYNC set to value 0, restart BOINC, I see the process use a full core.
- If I close BOINC, go to Control Panel -> System -> Advanced -> Environment Variables, set a System variable SWAN_SYNC set to value 1, restart BOINC, I see the process use a full core.
- If I close BOINC, remove the System variable SWAN_SYNC, restart BOINC, I see the process use a partial (approximately 1/12th of a) core.

This leads me to believe the feature is bugged. I would have thought the application would have acted differently, when setting the variable to 1 vs setting it to 0. It's only acting differently based on the EXISTENCE of the variable, not the SETTING of the variable. Bug?

Now I get to stay up all night, contemplating whether I want to actually use this. Sigh. Thanks for making in an option at least. We appreciate options, we really do.

I was so happy receiving just cuda55/cuda42 wus for the GTX660Ti and now I'm receiving cuda60 units that are all failing since my driver is old but was perfect for my cards and ubuntu system.

Hello guys,

there is also something wrong with some long WU's on Maxwell cards,

I'm on GTX750Ti here, Driver 334.21, Ubuntu 12.04.4 64 bit.

I have a A2ART4Ex04x21-GERARD_A2ART4E-1-14-RND8074_3 task, cuda 60 8.21 and after half an hour its at 0.2% done, CPU is at almost 100% while GPU is almost idle.

I had SWAN_SYNC=0 set as a User Variable, from way back, and it worked as soon as I used the 8.41 app version. It was the case that it should be set as an environmental variable and should be set to 0, but it use to work when set to other numbers including 1. However, I remember Gianni or Toni wasn't happy with it being set to other numbers - don't know why?

I found that the GPU usage rose by ~2% (to 92% and 94%) on my one W7 system (770 and 670; GK104 cards), but I am using more than 50% of the CPU's (100% now). At 50%, for me, I saw no significant difference from the drivers (actually newer drivers were slightly faster), but others found that their GK110 cards were slightly slower with the newer drivers. I wonder if that is still the case?

Is SWAN_SYNC available for Linux?

Peter_M, you completed other work with the 8.21 app, so it's probably not an app issue. It sounds like the WU is/was just running very slow. Check the GPU clocks in NVidia X server and if need be restart the application, system or even abort the WU. Are you running CPU tasks as well as GPU tasks? It doesn't look like it but if you are try to suspend the CPU work.

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skgiven,

SWAN_SYNC it has different meaning now - it merely needs to be present (set to any value at all, including 0) to have an effect.

Matt

In the other thread you said 8.41 would already have it. I have such a CUDA 6 WU running under Win 8.1. I created a user or system environment variable called SWAN_SYNC, set it to 0 and rebooted. However, CPU usage remains at 1.4 - 1.8% (8 threads), so it's obviously not working yet. Did I do anything wrong?

Guys, sorry for the confusion. After sleeping over it I changed nothing and came back just to find SWAN_SYNC working, making the app use a full core again. Can't quantify any performance gains yet, though.

Edit: for a statistically insufficient sample size of "1" I saw no change in performance (GTX660Ti, 335.23, Win 8.1, CPU not completely saturated). Which makes sense since otherwise I would have sticked to earlier drivers.

MrS

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Have had SWAN_SYNC set to 0 on all my machines. Also running with the <cpu_usage>1.0</cpu_usage> line in my app_config. Woke up today to see each machine has completed tasks on the 335 driver (XP and Win7) where CPU time is nearly equal to GPU time.

Each thread given to a GPUGrid task is now actually using the whole thread now. Yup, it is working. Thanks.

All tasks v8.21(cuda60) are failing in my Linux host with driver 304.88. My cards are GTx 660Ti.

What have I to change to run them properly?

Thanks for your help.

See the "Important new for Linux crunchers" post in the News.

Thanks, major issue I see. no time for it now.

Thank you skgiven,
it seemed to have been a one time issue, other longs are doing well, will report if I encounter it again. And I run tasks on CPU but have a core reserved for GPUGrid always.

Peter_M, you completed other work with the 8.21 app, so it's probably not an app issue. It sounds like the WU is/was just running very slow. Check the GPU clocks in NVidia X server and if need be restart the application, system or even abort the WU. Are you running CPU tasks as well as GPU tasks? It doesn't look like it but if you are try to suspend the CPU work.

So now it seems established that SWAN_SYNC reserves a whole CPU core. But is it any faster? If so, how much?

It's very easy to test, just close BOINC, create or remove the System Variable, and restart BOINC.

On one of my tests, where I temporarily suspended all projects except GPUGrid (such that no CPU tasks were interfering), I showed GPU Usage go from 93% without SWAN_SYNC, to 96% with SWAN_SYNC. So, that's ~3% speedup, for that sample, which should translate into a similar amount of task completion throughput. But since I run other CPU projects, I have decided to not use SWAN_SYNC.

It's very easy to test, just close BOINC, create or remove the System Variable, and restart BOINC.

On one of my tests, where I temporarily suspended all projects except GPUGrid (such that no CPU tasks were interfering), I showed GPU Usage go from 93% without SWAN_SYNC, to 96% with SWAN_SYNC. So, that's ~3% speedup, for that sample, which should translate into a similar amount of task completion throughput. But since I run other CPU projects, I have decided to not use SWAN_SYNC.

Thanks for the reply. I try to load the CPUs up to the point just before GPU performance starts degrading. At the moment the CPU tasks I'm running have long periods between checkpoints so restarting BOINC is not something I want to do. A 3% speedup doesn't sound like much if sacrificing a CPU task is the result. Since WU types show large differences in GPU usage, I wonder if SWAN_SYNC would have widely varying results?