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KVM: ppc: Implement in-kernel exit timing statistics

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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>
This commit is contained in:
Hollis Blanchard
2008-12-02 15:51:57 -06:00
committed by Avi Kivity
parent c5fbdffbda
commit 73e75b416f
13 changed files with 516 additions and 18 deletions
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102
arch/powerpc/kvm/timing.h Normal file
View File

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/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* Copyright IBM Corp. 2008
*
* Authors: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
*/
#ifndef __POWERPC_KVM_EXITTIMING_H__
#define __POWERPC_KVM_EXITTIMING_H__
#include <linux/kvm_host.h>
#include <asm/kvm_host.h>
#ifdef CONFIG_KVM_EXIT_TIMING
void kvmppc_init_timing_stats(struct kvm_vcpu *vcpu);
void kvmppc_update_timing_stats(struct kvm_vcpu *vcpu);
void kvmppc_create_vcpu_debugfs(struct kvm_vcpu *vcpu, unsigned int id);
void kvmppc_remove_vcpu_debugfs(struct kvm_vcpu *vcpu);
static inline void kvmppc_set_exit_type(struct kvm_vcpu *vcpu, int type)
{
vcpu->arch.last_exit_type = type;
}
#else
/* if exit timing is not configured there is no need to build the c file */
static inline void kvmppc_init_timing_stats(struct kvm_vcpu *vcpu) {}
static inline void kvmppc_update_timing_stats(struct kvm_vcpu *vcpu) {}
static inline void kvmppc_create_vcpu_debugfs(struct kvm_vcpu *vcpu,
unsigned int id) {}
static inline void kvmppc_remove_vcpu_debugfs(struct kvm_vcpu *vcpu) {}
static inline void kvmppc_set_exit_type(struct kvm_vcpu *vcpu, int type) {}
#endif /* CONFIG_KVM_EXIT_TIMING */
/* account the exit in kvm_stats */
static inline void account_exit_stat(struct kvm_vcpu *vcpu, int type)
{
/* type has to be known at build time for optimization */
BUILD_BUG_ON(__builtin_constant_p(type));
switch (type) {
case EXT_INTR_EXITS:
vcpu->stat.ext_intr_exits++;
break;
case DEC_EXITS:
vcpu->stat.dec_exits++;
break;
case EMULATED_INST_EXITS:
vcpu->stat.emulated_inst_exits++;
break;
case DCR_EXITS:
vcpu->stat.dcr_exits++;
break;
case DSI_EXITS:
vcpu->stat.dsi_exits++;
break;
case ISI_EXITS:
vcpu->stat.isi_exits++;
break;
case SYSCALL_EXITS:
vcpu->stat.syscall_exits++;
break;
case DTLB_REAL_MISS_EXITS:
vcpu->stat.dtlb_real_miss_exits++;
break;
case DTLB_VIRT_MISS_EXITS:
vcpu->stat.dtlb_virt_miss_exits++;
break;
case MMIO_EXITS:
vcpu->stat.mmio_exits++;
break;
case ITLB_REAL_MISS_EXITS:
vcpu->stat.itlb_real_miss_exits++;
break;
case ITLB_VIRT_MISS_EXITS:
vcpu->stat.itlb_virt_miss_exits++;
break;
case SIGNAL_EXITS:
vcpu->stat.signal_exits++;
break;
}
}
/* wrapper to set exit time and account for it in kvm_stats */
static inline void account_exit(struct kvm_vcpu *vcpu, int type)
{
kvmppc_set_exit_type(vcpu, type);
account_exit_stat(vcpu, type);
}
#endif /* __POWERPC_KVM_EXITTIMING_H__ */