Framebuffer and OpenCl

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Profile Darrell
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Message 1890933 - Posted: 20 Sep 2017, 14:33:29 UTC

I asked this question over on the Guru3d support forum for MSI Afterburner, but no one has provided an answer yet. So I'll ask here to see if anyone can answer. MSI Afterburner, a nifty program for monitoring and controlling GPUs has a graph for monitoring framebuffer usage called "FB usage, %". Of the various projects that I'm attached to, some of the OpenCL apps register usages of the framebuffer and some don't. The questions are what is this usage indicating, and what is the significance of usage or non-usage? Currently, the GPU is processing a PrimeGrid Genifer 22 task that is going to take another 3 to 4 days to complete, so I only have one screenshot to show what I'm asking about.

https://1drv.ms/i/s!ArIvftV8roEagXpbYch1Ux3pRZTV
... and still I fear, and still I dare not laugh at the Mad Man!

Queen - The Prophet's Song
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Profile ZalsterProject Donor
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Message 1890949 - Posted: 20 Sep 2017, 16:09:40 UTC - in response to Message 1890933.  
Last modified: 20 Sep 2017, 16:11:19 UTC

FB usage is front bus usage. It represents the amount of the pcie bandwidth the card is using at any given time. The bus connects the ram, cpu and the graphics card together so when the card is sending/ receiving more data the bus usage increases. Monitoring of this value is/was used by us when we were testing how many work units we could place on each card before saturation of the FB was achieved. It was also a good measure when testing the different commanldline parameters in the testing of the SoG. (I can't speak for petri's app since i don't how he tested this or if they ever did since my understanding is they only run 1 work unit per card with that Special cuda app)

So, I can't say why you would want to look at it unless you think you are saturating the FB somehow. Usually not for most people.

Hope this helps,

Zalster
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Message 1890967 - Posted: 20 Sep 2017, 16:45:56 UTC - in response to Message 1890949.  

Thank you for the explanation. The documentation for Afterburner leaves a lot to be desired and really doesn't explain what you see at times. I really don't use it, but was just curious as to what it showing and why some apps show usage and others don't.
... and still I fear, and still I dare not laugh at the Mad Man!

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Message boards : Number crunching : Framebuffer and OpenCl


 
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