when using a KVM.
There is no actual solution possible, but this gets us pretty close.
Typically when switching back to a FreeBSD box and moving the mouse
wild data is produced, because the protocol's validation/checksum
system is extremely weak it is impossible to determine that we're
out of sync before dropping several bogus packets to user land.
The actual solution that appears to offer the best clamping of
jitter is to buffer the mouse packets if we've not seen mouse
activity for more than .5 seconds. Then waiting to flush that data
for 1/20th of a second. If within that 20th of a second we get any
packets that do fail the weak test we drop the entire queue and
back off accepting data from the mouse for 2 seconds and then repeat
the whole deal.
You can still get _some_ jitter, notably if you switch to the FreeBSD
box, then move the mouse just enough to generate one or two packets.
Those packets may be bogus, but may still pass the validity check.
One way to finally kill the problem once and for all is to check
the initial packets for "wild" values. Typically one sees packets
in the +/-60 range during normal operation, however when bogus data
is generated it's typically near the outer range of +/-120 or more,
those packets would be a good candidate for dropping or clamping.
I've been running with this for several weeks now and it has
significantly helped me stay sane even with a piece of junk Belkin
KVM causing wild jitter each and every time I switch.
Lastly I'd like to note that my experience with Windows shows me that
somehow the Microsoft PS/2 driver typically avoids this problem, but
that may only be possible when running the mouse in a dumb-ed down PS/2
mode that Belkin recommends on their site.
cpu are added to a group.
- Don't place a cpu into the kseq_idle bitmask until all cpus in that group
have idled.
- Prefer idle groups over idle group members in the new kseq_transfer()
function. In this way we will prefer to balance load across full cores
rather than add further load a partial core.
- Before a cpu goes idle, check the other group members for threads. Since
SMT cpus may freely share threads, this is cheap.
- SMT cores may be individually pinned and bound to now. This contrasts the
old mechanism where binding or pinning would have allowed a thread to run
on any available cpu.
- Remove some unnecessary logic from sched_switch(). Priority propagation
should be properly taken care of in sched_prio() now.
with the sendsig code in the MD area. It is not safe to assume that all
the register conventions will be the same. Also, the way of producing
32 bit code (.code32 directives) in this file is amd64 specific.
The split-up code is derived from the ia64 code originally.
Note that I have only compile-tested this, not actually run-tested it.
The ia64 side of the force is missing some significant chunks of signal
delivery code.
- Replace overly-complicated (and buggy) -a logic with a much simpler
version: -a causes all interrupts to be displayed, otherwise only
those that have occurred are displayed. This removes the need for
any MD code.
- Instead of just making sure intrcnt is large enough, figure out the
exact size it needs to be. We derive nintr from this number, and we
don't want to risk printing garbage. Note that on sparc64, we end up
printing garbage anyway because the names of non-existent interrupts
are left uninitialized by the kernel.
Tested on: alpha, i386, sparc64
only turned up when running mac_test side by side with a transitioning
policy such as SEBSD. Make the NULL testing match
mac_test_execve_will_transition(), which already tested the vnode
label pointer for NULL.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
