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| author | Hollis Blanchard <hollisb@us.ibm.com> | 2008-12-02 15:51:57 -0600 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2008-12-31 16:55:41 +0200 |
| commit | 73e75b416ffcfa3a84952d8e389a0eca080f00e1 (patch) | |
| tree | 6195be5b0fa56235550679f35ca990093dd081ca /arch/powerpc/kvm/booke_interrupts.S | |
| parent | c5fbdffbda79254047ec83b09c1a61a3655d052a (diff) | |
| download | linux-73e75b416ffcfa3a84952d8e389a0eca080f00e1.tar.gz | |
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>
Diffstat (limited to 'arch/powerpc/kvm/booke_interrupts.S')
| -rw-r--r-- | arch/powerpc/kvm/booke_interrupts.S | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/arch/powerpc/kvm/booke_interrupts.S b/arch/powerpc/kvm/booke_interrupts.S index eb2186823e4e..084ebcd7dd83 100644 --- a/arch/powerpc/kvm/booke_interrupts.S +++ b/arch/powerpc/kvm/booke_interrupts.S @@ -107,6 +107,18 @@ _GLOBAL(kvmppc_resume_host) li r6, 1 slw r6, r6, r5 +#ifdef CONFIG_KVM_EXIT_TIMING + /* save exit time */ +1: + mfspr r7, SPRN_TBRU + mfspr r8, SPRN_TBRL + mfspr r9, SPRN_TBRU + cmpw r9, r7 + bne 1b + stw r8, VCPU_TIMING_EXIT_TBL(r4) + stw r9, VCPU_TIMING_EXIT_TBU(r4) +#endif + /* Save the faulting instruction and all GPRs for emulation. */ andi. r7, r6, NEED_INST_MASK beq ..skip_inst_copy @@ -375,6 +387,18 @@ lightweight_exit: lwz r3, VCPU_SPRG7(r4) mtspr SPRN_SPRG7, r3 +#ifdef CONFIG_KVM_EXIT_TIMING + /* save enter time */ +1: + mfspr r6, SPRN_TBRU + mfspr r7, SPRN_TBRL + mfspr r8, SPRN_TBRU + cmpw r8, r6 + bne 1b + stw r7, VCPU_TIMING_LAST_ENTER_TBL(r4) + stw r8, VCPU_TIMING_LAST_ENTER_TBU(r4) +#endif + /* Finish loading guest volatiles and jump to guest. */ lwz r3, VCPU_CTR(r4) mtctr r3 |