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>
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index eb24383..0f17124 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -28,6 +28,7 @@
#include <asm/cputable.h>
#include <asm/uaccess.h>
#include <asm/kvm_ppc.h>
+#include "timing.h"
#include <asm/cacheflush.h>
#include <asm/kvm_44x.h>
@@ -185,6 +186,9 @@
enum emulation_result er;
int r = RESUME_HOST;
+ /* update before a new last_exit_type is rewritten */
+ kvmppc_update_timing_stats(vcpu);
+
local_irq_enable();
run->exit_reason = KVM_EXIT_UNKNOWN;
@@ -198,7 +202,7 @@
break;
case BOOKE_INTERRUPT_EXTERNAL:
- vcpu->stat.ext_intr_exits++;
+ account_exit(vcpu, EXT_INTR_EXITS);
if (need_resched())
cond_resched();
r = RESUME_GUEST;
@@ -208,8 +212,7 @@
/* Since we switched IVPR back to the host's value, the host
* handled this interrupt the moment we enabled interrupts.
* Now we just offer it a chance to reschedule the guest. */
-
- vcpu->stat.dec_exits++;
+ account_exit(vcpu, DEC_EXITS);
if (need_resched())
cond_resched();
r = RESUME_GUEST;
@@ -222,20 +225,21 @@
vcpu->arch.esr = vcpu->arch.fault_esr;
kvmppc_booke_queue_irqprio(vcpu, BOOKE_IRQPRIO_PROGRAM);
r = RESUME_GUEST;
+ account_exit(vcpu, USR_PR_INST);
break;
}
er = kvmppc_emulate_instruction(run, vcpu);
switch (er) {
case EMULATE_DONE:
+ /* don't overwrite subtypes, just account kvm_stats */
+ account_exit_stat(vcpu, EMULATED_INST_EXITS);
/* Future optimization: only reload non-volatiles if
* they were actually modified by emulation. */
- vcpu->stat.emulated_inst_exits++;
r = RESUME_GUEST_NV;
break;
case EMULATE_DO_DCR:
run->exit_reason = KVM_EXIT_DCR;
- vcpu->stat.dcr_exits++;
r = RESUME_HOST;
break;
case EMULATE_FAIL:
@@ -255,6 +259,7 @@
case BOOKE_INTERRUPT_FP_UNAVAIL:
kvmppc_booke_queue_irqprio(vcpu, BOOKE_IRQPRIO_FP_UNAVAIL);
+ account_exit(vcpu, FP_UNAVAIL);
r = RESUME_GUEST;
break;
@@ -262,20 +267,20 @@
vcpu->arch.dear = vcpu->arch.fault_dear;
vcpu->arch.esr = vcpu->arch.fault_esr;
kvmppc_booke_queue_irqprio(vcpu, BOOKE_IRQPRIO_DATA_STORAGE);
- vcpu->stat.dsi_exits++;
+ account_exit(vcpu, DSI_EXITS);
r = RESUME_GUEST;
break;
case BOOKE_INTERRUPT_INST_STORAGE:
vcpu->arch.esr = vcpu->arch.fault_esr;
kvmppc_booke_queue_irqprio(vcpu, BOOKE_IRQPRIO_INST_STORAGE);
- vcpu->stat.isi_exits++;
+ account_exit(vcpu, ISI_EXITS);
r = RESUME_GUEST;
break;
case BOOKE_INTERRUPT_SYSCALL:
kvmppc_booke_queue_irqprio(vcpu, BOOKE_IRQPRIO_SYSCALL);
- vcpu->stat.syscall_exits++;
+ account_exit(vcpu, SYSCALL_EXITS);
r = RESUME_GUEST;
break;
@@ -294,7 +299,7 @@
kvmppc_booke_queue_irqprio(vcpu, BOOKE_IRQPRIO_DTLB_MISS);
vcpu->arch.dear = vcpu->arch.fault_dear;
vcpu->arch.esr = vcpu->arch.fault_esr;
- vcpu->stat.dtlb_real_miss_exits++;
+ account_exit(vcpu, DTLB_REAL_MISS_EXITS);
r = RESUME_GUEST;
break;
}
@@ -312,13 +317,13 @@
* invoking the guest. */
kvmppc_mmu_map(vcpu, eaddr, vcpu->arch.paddr_accessed, gtlbe->tid,
gtlbe->word2, get_tlb_bytes(gtlbe), gtlb_index);
- vcpu->stat.dtlb_virt_miss_exits++;
+ account_exit(vcpu, DTLB_VIRT_MISS_EXITS);
r = RESUME_GUEST;
} else {
/* Guest has mapped and accessed a page which is not
* actually RAM. */
r = kvmppc_emulate_mmio(run, vcpu);
- vcpu->stat.mmio_exits++;
+ account_exit(vcpu, MMIO_EXITS);
}
break;
@@ -340,11 +345,11 @@
if (gtlb_index < 0) {
/* The guest didn't have a mapping for it. */
kvmppc_booke_queue_irqprio(vcpu, BOOKE_IRQPRIO_ITLB_MISS);
- vcpu->stat.itlb_real_miss_exits++;
+ account_exit(vcpu, ITLB_REAL_MISS_EXITS);
break;
}
- vcpu->stat.itlb_virt_miss_exits++;
+ account_exit(vcpu, ITLB_VIRT_MISS_EXITS);
gtlbe = &vcpu_44x->guest_tlb[gtlb_index];
gpaddr = tlb_xlate(gtlbe, eaddr);
@@ -378,6 +383,7 @@
mtspr(SPRN_DBSR, dbsr);
run->exit_reason = KVM_EXIT_DEBUG;
+ account_exit(vcpu, DEBUG_EXITS);
r = RESUME_HOST;
break;
}
@@ -398,7 +404,7 @@
if (signal_pending(current)) {
run->exit_reason = KVM_EXIT_INTR;
r = (-EINTR << 2) | RESUME_HOST | (r & RESUME_FLAG_NV);
- vcpu->stat.signal_exits++;
+ account_exit(vcpu, SIGNAL_EXITS);
}
}
@@ -418,6 +424,8 @@
* before it's programmed its own IVPR. */
vcpu->arch.ivpr = 0x55550000;
+ kvmppc_init_timing_stats(vcpu);
+
return kvmppc_core_vcpu_setup(vcpu);
}