Hi,

Message: 1

Date: Thu, 15 Jan 2004 22:19:40 -0800 (PST)

From: rimas avizienis <funkrhythm@yahoo.com>

i have written a low latency coreaudio driver which

sends and receives UDP packets containing audio out

over the network interface to a special purpose piece

of hardware i've built. In order to get the

performance/latency/etc i needed when the machine was

running under a heavy load (doing real time processing

of live audio, etc) I had to modify the

AppleGMACEthernet.kext driver so that the main loop

in my coreaudio driver (get packet, copy buffers, call

taketimestamp, send a packet out) gets called at

primary interrupt time (highest priority in the

system) by using checkForInterrupt instead of just

interruptOccurred and having it call my coreaudio

driver. I basically bypassed the whole networking

stack.

You might need to do something of that sort...

That woud be more or less be exactly what I need, as I am also working on an audio over Ethernet application, except that I have a PowerMac on both ends. While I'd love to stay in userland wherever possible and don't have any plans to move the receiving side to the kernel, I'd be interested in any tweaks you did to the audio driver. My current audio driver .kext is using IOKit timers to replace the hardware interrupt, and I am experiencing problems when going below 128 frames @ 48kHz. I am in the lucky situation where bandwidth is not the problem (switched GBit), but if there are ways to get a lower latency I'd love to hear about them. -Stefan _______________________________________________ darwin-kernel mailing list | darwin-kernel@lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.