Ralf Mardorf ralf.mardorf at alice-dsl.net
Sat May 18 09:43:27 UTC 2013

On Sat, 2013-05-18 at 17:02 +1000, Ian Smith wrote:
> Re what Diane said, that seems also to be the case on linux

Hi :)

I reply from my "pro-audio" (bizarre term) Linux DAW ;). Are you talking
about real-time for the users?

On Linux even a vanilla kernel can be used with real-time abilities +
you can configure it to _full_ preemption and enable threadirqs when
booting, without patching the kernel. Im using a real-time patch for my
kernels, but the difference to a full preempted kernel are minimal.

Usually real-time permissions are given to the user by PAM,
http://www.jackaudio.org/linux_rt_config .

FWIW if on FreeBSD real-time is an issue, there still is the possibility
to take care about some other stuff, that could harm audio performance.

On my machine I unbind some USB ports, that share the IRQ with one of my
sound cards.

echo -n "0000:00:13.2" > /sys/bus/pci/drivers/ohci_hcd/unbind
echo -n "0000:00:13.4" > /sys/bus/pci/drivers/ohci_hcd/unbind

There isn't a difference for the performance on my machine, but perhaps
this can help on other machines.

You can stop services, bluetooth, cups, resp. remove drivers for
firewire, parallel port, printer.


It's said that editing PCI bus latency isn't a good idea and IIRC it has
got no impact to PCIe, but I might be mistaken.


Using Linux for pro-audio (this term simply is for "good working audio",
not only for professional usage ;) IMO still is luck of the draw, but
possible and this by running jackd as user.


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