Messages in this thread Patch in this message | | | From | Nikunj A Dadhania <> | Subject | Re: [RFC PATCH 0/4] Gang scheduling in CFS | Date | Wed, 04 Jan 2012 16:22:54 +0530 |
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On Mon, 02 Jan 2012 11:37:22 +0200, Avi Kivity <avi@redhat.com> wrote: > On 12/31/2011 04:21 AM, Nikunj A Dadhania wrote: > > > > GangV2: > > 27.45% ebizzy libc-2.12.so [.] __memcpy_ssse3_back > > 12.12% ebizzy [kernel.kallsyms] [k] clear_page > > 9.22% ebizzy [kernel.kallsyms] [k] __do_page_fault > > 6.91% ebizzy [kernel.kallsyms] [k] flush_tlb_others_ipi > > 4.06% ebizzy [kernel.kallsyms] [k] get_page_from_freelist > > 4.04% ebizzy [kernel.kallsyms] [k] ____pagevec_lru_add > > > > GangBase: > > 45.08% ebizzy [kernel.kallsyms] [k] flush_tlb_others_ipi > > 15.38% ebizzy libc-2.12.so [.] __memcpy_ssse3_back > > 7.00% ebizzy [kernel.kallsyms] [k] clear_page > > 4.88% ebizzy [kernel.kallsyms] [k] __do_page_fault > > Looping in flush_tlb_others(). Rik, what trace an we run to find out > why PLE directed yield isn't working as expected? > I tried some experiments by adding a pause_loop_exits stat in the kvm_vpu_stat.
Here are some observation related to Baseline-only(8vm case)
| ple_gap=128 | ple_gap=64 | ple_gap=256 | ple_window=2048 --------------+-------------+------------+-------------+---------------- EbzyRecords/s | 2247.50 | 2132.75 | 2086.25 | 1835.62 PauseExits | 7928154.00 | 6696342.00 | 7365999.00 | 50319582.00
With ple_window = 2048, PauseExits is more than 6times the default case
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From: Nikunj A. Dadhania <nikunj@linux.vnet.ibm.com>
Add Pause-loop-exit stats to kvm_vcpu_stat
Signed-off-by: Nikunj A. Dadhania <nikunj@linux.vnet.ibm.com>
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index b4973f4..be2e7f2 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -539,6 +539,7 @@ struct kvm_vcpu_stat { u32 hypercalls; u32 irq_injections; u32 nmi_injections; + u32 pause_loop_exits; }; struct x86_instruction_info; diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 579a0b5..29e90b7 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -4897,6 +4897,8 @@ out: static int handle_pause(struct kvm_vcpu *vcpu) { skip_emulated_instruction(vcpu); + ++vcpu->stat.pause_loop_exits; kvm_vcpu_on_spin(vcpu); return 1; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c38efd7..87433a8 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -149,6 +149,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { { "mmu_unsync", VM_STAT(mmu_unsync) }, { "remote_tlb_flush", VM_STAT(remote_tlb_flush) }, { "largepages", VM_STAT(lpages) }, + { "pause_loop_exits", VCPU_STAT(pause_loop_exits) }, { NULL } };
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