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authorSasha Levin <levinsasha928@gmail.com>2011-07-27 16:00:48 +0300
committerAvi Kivity <avi@redhat.com>2011-09-25 19:17:59 +0300
commit743eeb0b01d2fbf4154bf87bff1ebb6fb18aeb7a (patch)
tree5392464930f7e77131d65f32ba96ce4665307629 /arch/x86/kvm/irq.h
parent0d460ffc0956d2dbe12ca9f5f6aa0f8701ea9d73 (diff)
downloadop-kernel-dev-743eeb0b01d2fbf4154bf87bff1ebb6fb18aeb7a.zip
op-kernel-dev-743eeb0b01d2fbf4154bf87bff1ebb6fb18aeb7a.tar.gz
KVM: Intelligent device lookup on I/O bus
Currently the method of dealing with an IO operation on a bus (PIO/MMIO) is to call the read or write callback for each device registered on the bus until we find a device which handles it. Since the number of devices on a bus can be significant due to ioeventfds and coalesced MMIO zones, this leads to a lot of overhead on each IO operation. Instead of registering devices, we now register ranges which points to a device. Lookup is done using an efficient bsearch instead of a linear search. Performance test was conducted by comparing exit count per second with 200 ioeventfds created on one byte and the guest is trying to access a different byte continuously (triggering usermode exits). Before the patch the guest has achieved 259k exits per second, after the patch the guest does 274k exits per second. Cc: Avi Kivity <avi@redhat.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Sasha Levin <levinsasha928@gmail.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/x86/kvm/irq.h')
-rw-r--r--arch/x86/kvm/irq.h4
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/x86/kvm/irq.h b/arch/x86/kvm/irq.h
index 53e2d08..2086f2b 100644
--- a/arch/x86/kvm/irq.h
+++ b/arch/x86/kvm/irq.h
@@ -66,7 +66,9 @@ struct kvm_pic {
struct kvm *kvm;
struct kvm_kpic_state pics[2]; /* 0 is master pic, 1 is slave pic */
int output; /* intr from master PIC */
- struct kvm_io_device dev;
+ struct kvm_io_device dev_master;
+ struct kvm_io_device dev_slave;
+ struct kvm_io_device dev_eclr;
void (*ack_notifier)(void *opaque, int irq);
unsigned long irq_states[16];
};
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