Re: faketty_hijackled standalone kernel patch available

[Zoltan B. <zb...@fr...>]

Hi,

James van Zeeland =EDrta:
> Hi all.
>
> I have created a standalone faketty0.05_hijackled patch downloadable
> from my homepage; initially against 2.6.16.9, but it should apply
> broadly.
>
> http://members.westnet.com.au/vanzeeland
>
> I have been getting excellent results with realtime multimedia on a 3Gh=
z
> P4 - I am hoping to get realtime multi-console happenning, but there ar=
e
> some catches. While it works fine for most applications, indeed, it's
> overall latencies are down considerably, PCI video kills the mix; a
> multi-console machine will be good for realtime audio only if one uses
> the AGP console only, logging out all other consoles and leaving them
> alone.
>
> Any PCI console activity causes audible audio glitches. Bear in mind
> that we are recording 32bit audio files from 24bit sources at 96Khz, so
> there is a significantly higher load than using 16bit audio. over 4x.
>
> I am investigating ways to drastic lower the realtime performance impac=
t
> from PCI video cards.
> Is anyone aware of methods, kernel tweaks or tools that may assist in
> altering the PCI performance of the PCI video?
>  =20

Using "nice" or "renice" gives you the wanted effect.
It clearly shows on my PCI card if I start "supertux",
it skips very often but I can continue compiling on
the other console... On my system, the PCI VGA
blocks or throttles the PCI IDE in a similar way.

> We effectively don't care about video performance on pci consoles. If i=
t
> means they're noticably slower but audio operates in realtime, that's
> great.
>
> Does anyone have any info on how a USB console might load the system?
>  =20

USB used to have a CPU hog, you have to test recent kernels.

> I will be posting realtime kernels with faketty included soon,  followe=
d
> by a more 'vanilla' kernel sometime over the next week or tso.
>
> Apart from the audio glitches that you may not see or care about outsid=
e
> of pro-audio usage, the realtime kernels provide excellent desktop
> interactivity.
>
> J
>  =20

For a longer term solution, have you considered the following mainboards?
These two below are consumer-grade boards one can buy in the near future.

Gigabyte GA-G1975X, 2x PCIe x16 physical slots, 2x PCIe x4 physical
open ended slots, also usable with x16 cards (of these two, one is x1,
the other is x4 but x2 is the x1 slot is used)

Gigabyte GA-M59SLI-S5 Board, 3x PCIe x16 physical slots,
one of them is x4.

Workstation mainboard you can buy today:
Supermicro A+ *H8DCE, ***2 PCI-e x16 slots, 2 PCI-e x4 slots (x8 physical=
)

The nice thing about PCIe is that any card can work in any slot,
you just have to be able to plug them together. The card and the
slot controller negotiate the common wiring and use the highest
speed both can use. That means that one can cut the end of the slot
so an x16 card can be used in any lower grade slot, as Gigabyte
proved it with GA-G1975X.

Best regards,
Zolt=E1n b=F6sz=F6rm=E9nyi