On May 9, 2012, at 7:14 AM, Ph.T wrote: > . in a pre-emptive OS there should be no freezing; > given the new concurrency model > that includes the use of the graphics processor GPU > to do the system's non-graphics processing,
Well, the GPU can _occasionally_ be used to do some non-graphics work, typically tasks that are highly parallelizable. I’d reckon this happens most often in games, less in general purpose software. > my current guess is that the freezes happen when > something goes wrong in the GPU, > and the CPU is just waiting forever . > . the CPU needs to have some way of getting control back, > and sending an exception message to > any of the processes that were affected by the hung-up GPU . > . could any of Apple's developers > correct this theory or comment on it ? OS freezes tend to happen when kernel-level code gets into an infinite loop or deadlock. Sure there “should be no freezing” but there should be no bugs either, and that’s never true. (It’s exacerbated by the fact that some 3rd party device drivers need to run in kernel space.) _Some_ system freezes are due to the GPU completely locking up, usually due to a bug in the GPU vendor’s driver. My understanding is that when this happens it’s not really possible for the GPU to recover without a system reset. The CPU is probably still OK, but that doesn’t do any good if it can’t access the display. —Jens _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
