site_archiver@lists.apple.com Delivered-To: darwin-kernel@lists.apple.com At 11:18 -0500 on 12/26/06, Josh Rodatus wrote: How often are you writing to the socket and ow much data are you writing? My first guess would be that your writing so often that the constants calls out to the driver is causing the system to stutter. I'm writing 2048 bytes of data every time the audio stream calls my AudioIOFunction >function, about every 1/100 of a second. My gut reaction is that that sounds like an awful lot of bouncing back and forth between the kernel and user space. One simple thing to try would be reducing the frequency of your writes- queue the data up and do larger writes. Someone suggested a shared ring buffer, and I can see some very attractive advantages in that. It sounds like your just doing display, which means you don't _really_ care how accurate the data in the buffer is. If latency is becoming an issue, your much rather lose data and hope to sync up in the future rather than try to stay to synchronized. It sounds like you could basically get away with almost no "communication" between kernel and user space. Basically your app hands the kernel a memory buffer, the kernel writes data into it, and your app reads data out of it. If the kernel gets ahead of you, you lose data in the buffer- but you didn't want that data anyway, since it's old data. Just to share credit, this technique is similar to how isochronous transfers are handled by FireWire. -- ______________________________________________________ Arguing with an engineer is like wrestling with a pig in mud. After a while, you realize the pig is enjoying it. ______________________________________________________ Kevin Elliott <mailto:kelliott@mac.com> AIM/iChatAV: kelliott@mac.com (video chat available) ______________________________________________________ _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.a... This email sent to site_archiver@lists.apple.com