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Old 07-22-06, 11:17 AM   #97
zbiggy
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Default Re: Slow AA text rendering in KDE

There could be another reason for not having slowness on geforce 6150. I use source based distro: lunar-linux with all code optimized for my Athlon64 with SSE3. So the speed I get can be effect of fast code execution on CPU - not the GPU acceleration. It is better to ask someone who use Geforce 61xx on 586 optimized binary distro. The results would be more real than mine.
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Old 07-22-06, 10:25 PM   #98
d13f00l
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Default Re: Slow AA text rendering in KDE

Quote:
Originally Posted by Linuxhippy
3.) Well then I whish you a lot of fun with XFCE. Keep in mind you're GPU practically does nothing more than displaying the stuff calculated by you CPU *lol
Its a bit like changing your car just because with the tires you put onto it you can't driver more than 50km/h.
That's how pretty much any game made in DirectDraw and SDL work, and how computers have worked for ages. And hey, I can scroll around firefox and subpixel hinted text without my CPU usage hiking to 100%, so GTK is better optimzed SOMEWHERE. Maybe it keeps a few copies of the text prerendered, so it only has to render once. Even if the text was rendered once in software, and all copying thereafter was done in software, it would still be faster than rerendering the text every time in hardware.

I have a bunch of nvidia cards lying around, my current is a GF 6200 AGP, it's slow as heck in KDE w/ subpixel hinting, as is my GF4MX, and my Ti4200. There're all fine in GTK apps.

Even if I switch to the Vesa driver, most KDE applications are still slower than GTK applications at subpixel rendering. Ie, how kwrite sucks, and how kedit is fine. KDE is doing something wrong, somewhere, and they refuse to accept that. I asked the guy who closed the bug I opened on kdebugs why it was closed. He said he experienced no slowdowns. I asked what kind of system he had...quad dual core xeon 3.0ghz and 2gb of ram. Gee, I wonder why his PC was fine.

The problem happens in all drivers, and on all cards, I gaurentee it. I spent so many hours switching video cards and pulling out my hair trying to find the cause.

If you have a 500mhz k62 with a Geforce 2mx, and it's faster than a 6600GT and an athlon 64 3400, it doesn't matter unless you're using the same hard drive to test them both, with the same software and everything. You can't single out the problem without doing so, it's impossible. There are too many variables.

If you can test several Nvidia video cards in your PC, and if an older one actually is faster than a newer one _IN THE SAME PC_, Nvidia _WILL_ consider this a driver bug and it _WILL_ be investigated and fixed(eventually...har har ) by Nvidia. No one has been able to do this, I've tried, and I've given up.

Last edited by d13f00l; 07-22-06 at 10:43 PM.
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Old 07-22-06, 10:52 PM   #99
firephoto
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Default Re: Slow AA text rendering in KDE

Quote:
Originally Posted by d13f00l
The problem happens in all drivers, and on all cards, I gaurentee it.
No, it doesn't.

Quote:
If you can test several Nvidia video cards in your PC, and if an older one actually is faster than a newer one _IN THE SAME PC_, Nvidia _WILL_ consider this a driver bug and it _WILL_ be investigated and fixed(eventually...har har ) by Nvidia. No one has been able to do this, I've tried, and I've given up.
Several here and elsewhere have done this. I changed cards, problem appeared, nothing else changed. I know it affects 6800gt cards with supported drivers, and it even affects a 5600 card with the same affected drivers, what it doesn't affect (as bad) are older drivers that only work with pre-6*** cards but that's of no use because a 6800 card won't work with those older drivers and most likely they won't work with current kernels.
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Old 07-23-06, 03:15 AM   #100
Linuxhippy
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Default Re: Slow AA text rendering in KDE

Quote:
Originally Posted by d13f00l
If you have a 500mhz k62 with a Geforce 2mx, and it's faster than a 6600GT and an athlon 64 3400, it doesn't matter unless you're using the same hard drive to test them both, with the same software and everything. You can't single out the problem without doing so, it's impossible. There are too many variables.
Well I've a Duron800/FX5200 which is 4 times faster rendering subpixel text than my AMD64/GF6600 and it was _confirmed_ by nvidia that this is a hw-design-problem. So maybe you'll investigate a bit about the whole story before shouting?!

Quote:
and how computers have worked for ages
GDI was hw-accalerated as long as I can remeber (also X11) and DirectDraw is a dead api which won't be supported any longer, just because Direct3D can do all that but much more _with_ accaleration.
Furthermore DDraw and SDL were designed that you create your images _once_ upload them to vram and then draw these images over and over on a hw-accalerated surface - so except a step which could be compared to texture uploading only hw-accalerated operations are performed.

lg Clemens
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Old 07-23-06, 03:16 AM   #101
d13f00l
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Default Re: Slow AA text rendering in KDE

Quote:
Originally Posted by firephoto
No, it doesn't.
what it doesn't affect (as bad) are older drivers that only work with pre-6*** cards but that's of no use because a 6800 card won't work with those older drivers and most likely they won't work with current kernels.
Right. The problem wasn't there in the older drivers because subpixel hinting was accelerated in prior driver releases. It was disabled _ON PURPOSE_ because it didn't work right.

With the latest drivers, it seems to happen on all cards I try.
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Old 07-23-06, 03:18 AM   #102
d13f00l
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Default Re: Slow AA text rendering in KDE

Quote:
Originally Posted by Linuxhippy
Well I've a Duron800/FX5200 which is 4 times faster rendering subpixel text than my AMD64/GF6600 and it was _confirmed_ by nvidia that this is a hw-design-problem. So maybe you'll investigate a bit about the whole story before shouting?!
lg Clemens
Can you link me to that info where it was confirmed? A duron can totally be faster than an amd64 if the amd64 is running borked software(broken library, Xorg, etc) and the duron isn't.
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Old 07-23-06, 03:36 AM   #103
d13f00l
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Default Re: Slow AA text rendering in KDE

Quote:
Originally Posted by Linuxhippy
GDI was hw-accalerated as long as I can remeber (also X11) and DirectDraw is a dead api which won't be supported any longer, just because Direct3D can do all that but much more _with_ accaleration.
http://www.codeproject.com/bitmap/DFB_vs_DIB.asp
I guess it's either, like SDL. I never knew that.
I'm pretty tired and cranky.

I'm going to have to play w/ HW accelerated 2d. Whenever I code, I usually keep things in system ram for simplicity, and it's pretty fast. I try to write the best code possible, and do as few blits as possible and keep as much buffered as possible. Java seems to have an interesting way of handling 2d acceleration, it has Volatile images, if/when they get deleated they just get set to null and you can reallocate them. No having to manage video ram yourself

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Old 07-23-06, 07:36 AM   #104
Linuxhippy
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Default Re: Slow AA text rendering in KDE

Quote:
Originally Posted by d13f00l
Java seems to have an interesting way of handling 2d acceleration, it has Volatile images, if/when they get deleated they just get set to null and you can reallocate them. No having to manage video ram yourself
Well as far as I know you normally also don't have to manage video ram yourself.
X11 pixmaps and OpenGL textures are both hw acalerated (well I think almost any driver supports these primitives) and you don't have to take care about surface loss or memory management.

lg Clemens
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Old 07-23-06, 07:46 AM   #105
Linuxhippy
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Default Re: Slow AA text rendering in KDE

Quote:
Originally Posted by d13f00l
Can you link me to that info where it was confirmed? A duron can totally be faster than an amd64 if the amd64 is running borked software(broken library, Xorg, etc) and the duron isn't.
No, same software stack, same drivers, averything else. And according to AeronP these numbers make sence (I asked him how this is possible).

Well maybe "design-problem" is a bit too dramatic, but the "problem" lies in hardware, maybe PCI-X is the problem.

Have a look here: http://www.nvnews.net/vbulletin/show...ccess+patterns
-------------------------------------------------------------
My question:
But then why does a FX5200 outperform a GF6600 powered system with a much faster CPU by a factor of 2?
Have there been some regressions in chip-design which cause this slowdown?

Answer:
It has to do with bus access patterns. I'm afraid I can't go into a lot of detail.
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Old 07-23-06, 03:53 PM   #106
SaTaN0rX
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Default Re: Slow AA text rendering in KDE

Quote:
My question:
But then why does a FX5200 outperform a GF6600 powered system with a much faster CPU by a factor of 2?
Have there been some regressions in chip-design which cause this slowdown?

Answer:
It has to do with bus access patterns. I'm afraid I can't go into a lot of detail.
so it's the PCIe bus that kicks in.
<irony> Thats all nvidias fault as nvidia has invented the PCIe bus </irony>

ok, but to see things as they are: AGP is dead, and phased out in favor of PCIe.

so there is nothing that nvidia can do about this problem. it's up tp trolltech
or kde to solve it.
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Old 07-23-06, 09:25 PM   #107
d13f00l
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Default Re: Slow AA text rendering in KDE

So, rendering subpixel hinted text w/ a PCI-E card comes out even slower than doing it with an AGP card? That's pretty scary...all my cards are AGP and it's already too slow to actually have subpixel hinting enabled in KDE without wanting to drive a stake through my skull....

Last edited by d13f00l; 07-23-06 at 09:38 PM.
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Old 07-24-06, 12:55 AM   #108
Linuxhippy
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Default Re: Slow AA text rendering in KDE

Quote:
Originally Posted by SaTaN0rX
so there is nothing that nvidia can do about this problem. it's up tp trolltech
or kde to solve it.
<ironie>
Yes you're right. Man why I didn't see it before - nvidia is so great.
I should have considered it before: The application which requests text-rendering is the problem, not the driver/hw actually doing the job worng. I write trolltech that they should remove all text rendering needs out of QT and use smbols instead.
</ironie>

There are several things which could be done:

1.) Batch drawing commands a bit and try to readback larger areas. This would help programs with a lot of text (konsole, kwrite).

2.) Provide accaleration for boards capable of executing shaders (FX5200 and up). This would be a very good long-term solution however I doubt lower-end cards (FX5200, GF6200) will benefit a lot.

lg Clemens
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