linux/arch/powerpc/kvm/Kconfig
Hollis Blanchard 73e75b416f KVM: ppc: Implement in-kernel exit timing statistics
Existing KVM statistics are either just counters (kvm_stat) reported for
KVM generally or trace based aproaches like kvm_trace.
For KVM on powerpc we had the need to track the timings of the different exit
types. While this could be achieved parsing data created with a kvm_trace
extension this adds too much overhead (at least on embedded PowerPC) slowing
down the workloads we wanted to measure.

Therefore this patch adds a in-kernel exit timing statistic to the powerpc kvm
code. These statistic is available per vm&vcpu under the kvm debugfs directory.
As this statistic is low, but still some overhead it can be enabled via a
.config entry and should be off by default.

Since this patch touched all powerpc kvm_stat code anyway this code is now
merged and simplified together with the exit timing statistic code (still
working with exit timing disabled in .config).

Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:41 +02:00

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#
# KVM configuration
#
menuconfig VIRTUALIZATION
bool "Virtualization"
---help---
Say Y here to get to see options for using your Linux host to run
other operating systems inside virtual machines (guests).
This option alone does not add any kernel code.
If you say N, all options in this submenu will be skipped and
disabled.
if VIRTUALIZATION
config KVM
bool
select PREEMPT_NOTIFIERS
select ANON_INODES
config KVM_440
bool "KVM support for PowerPC 440 processors"
depends on EXPERIMENTAL && 44x
select KVM
---help---
Support running unmodified 440 guest kernels in virtual machines on
440 host processors.
This module provides access to the hardware capabilities through
a character device node named /dev/kvm.
If unsure, say N.
config KVM_EXIT_TIMING
bool "Detailed exit timing"
depends on KVM
---help---
Calculate elapsed time for every exit/enter cycle. A per-vcpu
report is available in debugfs kvm/vm#_vcpu#_timing.
The overhead is relatively small, however it is not recommended for
production environments.
If unsure, say N.
config KVM_TRACE
bool "KVM trace support"
depends on KVM && MARKERS && SYSFS
select RELAY
select DEBUG_FS
default n
---help---
This option allows reading a trace of kvm-related events through
relayfs. Note the ABI is not considered stable and will be
modified in future updates.
source drivers/virtio/Kconfig
endif # VIRTUALIZATION