On 2/9/08, H. Peter Anvin <[EMAIL PROTECTED]> wrote: > Blue Swirl wrote: > > On 2/9/08, Rob Landley <[EMAIL PROTECTED]> wrote: > >> Here's a patch Peter Anvin wrote so the serial I/O doesn't flood the > >> kernel. > > > > The patch looks OK, but the throttling should benefit all devices, as > > discussed here: > > http://lists.gnu.org/archive/html/qemu-devel/2007-12/msg00283.html > > I strongly disagree with the sentiments in that post. > > This is not a matter of rate throttling, but simulated FIFO exhaustion > -- they are NOT the same thing. Simulated FIFO exhaustion is > functionally equivalent to making sure there are interrupt windows > opened in an otherwise-too-long critical section; it doesn't constrain > any particular flow rate, as it still permits another interrupt to > immediately come in. > > If you look at the patch, there are no timing dependencies; the only > parameter is the depth of the virtual queue. The exhaustion is > completely controlled by target OS access patterns.
Thanks, this clarified the difference. But I'll rephrase my original comment: The patch looks OK, but the simulated FIFO exhaustion should benefit all devices, as discussed here: http://lists.gnu.org/archive/html/qemu-devel/2007-12/msg00283.html
