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| author | Paolo Bonzini <pbonzini@redhat.com> | 2015-08-12 15:38:18 +0200 |
|---|---|---|
| committer | Stefan Weil <sw@weilnetz.de> | 2015-09-24 20:52:28 +0200 |
| commit | 7c9b2bf67775ecc1359ce973580807d173e7f710 (patch) | |
| tree | 344a675e9af8e8885444247dc18aab45710bdcc0 /.gitignore | |
| parent | a246a01631f90230374c2b8ffce608232e2aa654 (diff) | |
| download | qemu-7c9b2bf67775ecc1359ce973580807d173e7f710.zip qemu-7c9b2bf67775ecc1359ce973580807d173e7f710.tar.gz qemu-7c9b2bf67775ecc1359ce973580807d173e7f710.tar.bz2 | |
qemu-thread: add a fast path to the Win32 QemuEvent
QemuEvents are used heavily by call_rcu. We do not want them to be slow,
but the current implementation does a kernel call on every invocation
of qemu_event_* and won't cut it.
So, wrap a Win32 manual-reset event with a fast userspace path. The
states and transitions are the same as for the futex and mutex/condvar
implementations, but the slow path is different of course. The idea
is to reset the Win32 event lazily, as part of a test-reset-test-wait
sequence. Such a sequence is, indeed, how QemuEvents are used by
RCU and other subsystems!
The patch includes a formal model of the algorithm.
Tested-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Diffstat (limited to '.gitignore')
0 files changed, 0 insertions, 0 deletions