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Kernel Dump msg S/C/F 11/2/11 - Page fault

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Re: Kernel Dump msg S/C/F 11/2/11 - Page fault

Postby maschoen » Tue May 10, 2016 6:30 am

sheran.vaz wrote:I'm not sure if my GUI is actually contributing to the page fault, but is it possible to reduce the GUI's CPU utilisation by keeping my application as is? Also I don't see any utilisation in io-display driver.


I don't think I understand your question. You seem to be asking: by changing nothing, can you (magically?) reduce the GUI's cpu utilization. How on earth would expect that to happen?
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Re: Kernel Dump msg S/C/F 11/2/11 - Page fault

Postby Tim » Tue May 10, 2016 2:58 pm

Are you running in release mode or debug mode? Compiling in release mode will increase your speed.

Why does it matter if your utilizing 70% of your CPU? Do you still have a lot of other code / processes that are still to be developed / added and your worried about needing more than 100% CPU capacity?

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Re: Kernel Dump msg S/C/F 11/2/11 - Page fault

Postby sheran.vaz » Tue May 10, 2016 5:01 pm

Yes, i have other processes running, The Page Fault seem to happen when there is more CPU utilisation by different processes. Therefore was wondering if there are better ways to improve the GUI performance.
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Re: Kernel Dump msg S/C/F 11/2/11 - Page fault

Postby sheran.vaz » Tue May 10, 2016 5:32 pm

maschoen wrote:
sheran.vaz wrote:I'm not sure if my GUI is actually contributing to the page fault, but is it possible to reduce the GUI's CPU utilisation by keeping my application as is? Also I don't see any utilisation in io-display driver.


I don't think I understand your question. You seem to be asking: by changing nothing, can you (magically?) reduce the GUI's cpu utilization. How on earth would expect that to happen?


I do agree the human eye can not grasp what was displayed, if it keeps changing every 200ms(only the numbers after the decimal keep changing frequently).
There are other places the issue is observed, like i have a busy wheel which keeps ticking very 100ms. After i changed the timing to 500ms, i dont see it much often now. There are other visualization that the GUI does at different places. Therefore was wondering would changing something in the underlying layer provide better performance.
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Re: Kernel Dump msg S/C/F 11/2/11 - Page fault

Postby maschoen » Tue May 10, 2016 5:50 pm

sheran.vaz wrote:
maschoen wrote:
sheran.vaz wrote: changing something in the underlying layer .


There is only one thing I can think of in this category. If you are running with an non-native video driver, for example the VESA driver, then switching to a native driver if one exists might speed things up. Video cards can have acceleration, specifically for biting data to the memory map. This has to be implemented in the driver.
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Re: Kernel Dump msg S/C/F 11/2/11 - Page fault

Postby sheran.vaz » Wed May 11, 2016 5:54 am

Right now the io-display uses devg-vga.so. Should i use devg-intelHd.so as my pci output shows
Class = Display (VGA)
Vendor ID = 8086h, Intel Corporation
Device ID = 116h, Unknown Unknown

device ID 0116h is:
Chip Number: intel core i3
Chip Description: Intel HD Graphics 3000

Or should i use devg-i830 or devg-i810? Has anyone tried this before?
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Re: Kernel Dump msg S/C/F 11/2/11 - Page fault

Postby maschoen » Wed May 11, 2016 7:40 am

sheran.vaz wrote:Right now the io-display uses devg-vga.so. Should i use devg-intelHd.so as my pci output shows
Class = Display (VGA)
Vendor ID = 8086h, Intel Corporation
Device ID = 116h, Unknown Unknown

device ID 0116h is:
Chip Number: intel core i3
Chip Description: Intel HD Graphics 3000

Or should i use devg-i830 or devg-i810? Has anyone tried this before?


Run the

$ pci

command.

Look up the Vendor-ID:Device-ID in QNX's hardware web resource. This will tell you which if any native driver to use. Or just try them all and see which works.
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Re: Kernel Dump msg S/C/F 11/2/11 - Page fault

Postby denkelly » Wed May 11, 2016 11:19 am

>>> Also I don't see any utilisation in io-display driver.
So you are using "gf". What display driver? vesa? svga?
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Re: Kernel Dump msg S/C/F 11/2/11 - Page fault

Postby sheran.vaz » Wed May 11, 2016 4:35 pm

denkelly wrote:>>> Also I don't see any utilisation in io-display driver.
So you are using "gf". What display driver? vesa? svga?


pidin mem shows devg-svga.so
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Re: Kernel Dump msg S/C/F 11/2/11 - Page fault

Postby denkelly » Wed May 11, 2016 5:37 pm

The "svga" driver is switching the processsor to "real" (16-bit) mode and back (to 32-bit) whenever it needs to run svga BIOS code. I suspect that is behind the kernel crash.

You should try the intelhd driver. Try specifying the vid/did on the command line if it does not automatically load. (i830/i810.gma9xx drivers are mostly for Atom parts - unlikely to work on i3).

In Qt are you using widgets or QML? QML tends to be more efficient than the traditional widgets from my experience.
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Re: Kernel Dump msg S/C/F 11/2/11 - Page fault

Postby sheran.vaz » Wed May 11, 2016 8:31 pm

denkelly wrote:The "svga" driver is switching the processsor to "real" (16-bit) mode and back (to 32-bit) whenever it needs to run svga BIOS code. I suspect that is behind the kernel crash.

You should try the intelhd driver. Try specifying the vid/did on the command line if it does not automatically load. (i830/i810.gma9xx drivers are mostly for Atom parts - unlikely to work on i3).

In Qt are you using widgets or QML? QML tends to be more efficient than the traditional widgets from my experience.


Does making the processor switch between real mode and 32bit mode causes more overhead?

And intelhd does not do the switching to real mode?

Qt is base on widgets.
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Re: Kernel Dump msg S/C/F 11/2/11 - Page fault

Postby maschoen » Wed May 11, 2016 9:04 pm

sheran.vaz wrote:Does making the processor switch between real mode and 32bit mode causes more overhead?


Yes, quite a bit.

And intelhd does not do the switching to real mode?


That is right. The switching to real mode is to take advantage of the real mode BIOS code which is on the video card. Since QNX is running in virtual mode, to execute this code requires switching modes. A native driver knows how to talk to the hardware directly so it doesn't need the BIOS and therefore doesn't need to switch.

Qt is base on widgets.


Most Qt programming is based on widgets, yes. But QML is language provided with Qt that allows programming outside of widgets.

https://en.wikipedia.org/wiki/QML
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Postby denkelly » Thu May 12, 2016 12:42 am

>>>Does making the processor switch between real mode and 32bit mode causes more overhead?
Not only does it cause overhead, it introduces jitter to the real-time scheduling. BIOS code can never be pre-empted since 32-bit QNX interrupt-handlers (and the scheduler) can't run during real mode.
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Re: Kernel Dump msg S/C/F 11/2/11 - Page fault

Postby sheran.vaz » Thu May 12, 2016 8:19 am

After using Intelhd the gui utilization reduced atleast by 24%. But the intelhd driver that came with 6.5 sp1 installation showed a black screen, downloaded the experimental driver and it worked. So far haven't seen the issue.

Thanks the inputs.

Is svga driver not safe to use? Does Intelhd affect 3d rendering?(for now I have tested only 2d rendering)
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Re: Kernel Dump msg S/C/F 11/2/11 - Page fault

Postby maschoen » Thu May 12, 2016 5:32 pm

sheran.vaz wrote:Is svga driver not safe to use?


Switching back and forth between virtual and real mode requires BIOS support. It's possible your crash problem is related in a deficiency in the BIOS.


Does Intelhd affect 3d rendering?(for now I have tested only 2d rendering)

[/quote]

If by 3d rendering, you mean using Open GL ES, the Open GL ES code either works purely in software or takes advantage of hardware acceleration. If the video chip you are using is supported, then you will get much faster 3d rendering then if not. I don't know if the intelhd is supported.
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