13.12.2011 08:31, Marko Ristola:
>
> Hi
>
> Here is a patch that went into Linus GIT this year.
> It reduces the number of DMA transfer interrupts into one third.
> Linus released 2.6.38.8 doesn't seem to have this patch yet
Good news, combining this patch with IRQ management fixes the problem for me.
Status:
* Stock 2.6.38.8 mantis, no IRQ management: glitches
* Stock 2.6.38.8 mantis, with IRQ management: glitches
* Patched 2.6.38.8 mantis, no IRQ management: glitches (less)
* Patched 2.6.38.8 mantis, with IRQ management: very few glitches
* Same as above, but latency_timer set to 0xff: no glitches in one hour
The patch was applied to 2.6.38.8 (in Ubuntu terms: 2.6.38-13-generic-pae).
Tests involved having VDR record on three different transponders at the same
time, which means lots of IO and all three cards active at once.
For IRQ management I tried both 'irqbalancer' and manual setting with IRQ
affinity (which is basicly what irqbalancer does).
I tried playing with the latency timer on the other scenarios, not only the
last one, but all had glitches anyways.
Not sure what to conclude with:
- Unfortunate IRQ handling on this CPU (two and two share IRQ handling)?
- Too many interrupts generated by driver (design issues)?
- Driver not handling SMP gracefully?
...or a combination?
Your patch is definately needed. Is there anything I can do to help getting
it in?
--
Vidar Tyldum
vidar@xxxxxxxxxx PGP: 0x3110AA98
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