linux/arch/powerpc
Hollis Blanchard d4cf3892e5 KVM: ppc: optimize irq delivery path
In kvmppc_deliver_interrupt is just one case left in the switch and it is a
rare one (less than 8%) when looking at the exit numbers. Therefore we can
at least drop the switch/case and if an if. I inserted an unlikely too, but
that's open for discussion.

In kvmppc_can_deliver_interrupt all frequent cases are in the default case.
I know compilers are smart but we can make it easier for them. By writing
down all options and removing the default case combined with the fact that
ithe values are constants 0..15 should allow the compiler to write an easy
jump table.
Modifying kvmppc_can_deliver_interrupt pointed me to the fact that gcc seems
to be unable to reduce priority_exception[x] to a build time constant.
Therefore I changed the usage of the translation arrays in the interrupt
delivery path completely. It is now using priority without translation to irq
on the full irq delivery path.
To be able to do that ivpr regs are stored by their priority now.

Additionally the decision made in kvmppc_can_deliver_interrupt is already
sufficient to get the value of interrupt_msr_mask[x]. Therefore we can replace
the 16x4byte array used here with a single 4byte variable (might still be one
miss, but the chance to find this in cache should be better than the right
entry of the whole array).

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 16:52:23 +02:00
..
boot Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc 2008-12-28 16:54:33 -08:00
configs Merge branch 'next' of master.kernel.org:/pub/scm/linux/kernel/git/jwboyer/powerpc-4xx into next 2008-12-17 11:01:43 +11:00
include/asm KVM: ppc: optimize irq delivery path 2008-12-31 16:52:23 +02:00
kernel KVM: ppc: create struct kvm_vcpu_44x and introduce container_of() accessor 2008-12-31 16:52:22 +02:00
kvm KVM: ppc: optimize irq delivery path 2008-12-31 16:52:23 +02:00
lib Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc 2008-12-28 16:54:33 -08:00
math-emu powerpc: Add SPE/EFP math emulation for E500v1/v2 processors. 2008-12-03 08:19:16 -06:00
mm Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc 2008-12-28 16:54:33 -08:00
oprofile powerpc/cell/OProfile: Fix on-stack array size in activate spu profiling function 2008-10-31 16:13:51 +11:00
platforms Merge branch 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-12-30 16:10:19 -08:00
sysdev Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc 2008-12-28 16:54:33 -08:00
xmon powerpc: Prepare xmon_save_regs for use with kdump 2008-12-23 15:13:28 +11:00
Kconfig Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc 2008-12-28 16:54:33 -08:00
Kconfig.debug powerpc: Allow the max stack trace depth to be configured 2008-12-03 20:46:35 +11:00
Makefile powerpc: Remove unncessary SPE related compiler flag 2008-12-03 08:19:10 -06:00