Messages in this thread | | | Date | Wed, 13 Sep 2017 17:14:09 +0800 | From | "Du, Changbin" <> | Subject | Re: Does perf-annotate work correctly? |
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Here is another example which may be easy to analyse. I beleve that something wrong in parsing objdump output.
The 'test %esi,%esi' is not of 'if (unlikely(error))', but 'if (!idtv_info_valid)'.
perf annotate of function vmx_complete_interrupts(): vmx_complete_interrupts /lib/modules/4.13.0+/kernel/arch/x86/kvm/kvm-intel.ko Percent│ mov 0x4590(%rdi),%esi ▒ │ vmx_cancel_injection(): ▒ │ vmcs_read32(VM_ENTRY_INTR_INFO_FIELD), ▒ │ VM_ENTRY_INSTRUCTION_LEN, ▒ │ VM_ENTRY_EXCEPTION_ERROR_CODE); ▒ │ ▒ │ vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, 0); ▒ │ } ▒ │ movb $0x0,0x32c8(%rdi) ▒ │ __vmx_complete_interrupts(): ▒ │ movb $0x0,0x1a7c(%rdi) ▒ │ movb $0x0,0x1a88(%rdi) ▒ │ __vmcs_writel(): ▒ │ u8 error; ▒ │ ▒ │ asm volatile (__ex(ASM_VMX_VMWRITE_RAX_RDX) "; setna %0" ▒ │ : "=q"(error) : "a"(value), "d"(field) : "cc"); ▒ │ if (unlikely(error)) ▒ │ vmwrite_error(field, value); ▒ 0.02 │ test %esi,%esi ▒ │ ↓ js 25 ▒ 99.98 │ ← retq ▒ │25: push %rbp ▒ │ mov $0x440a,%ecx ▒ │ mov $0x440c,%edx ▒ │ vmx_complete_interrupts(): ◆ │ break; ▒ │ } ▒ │ } ▒ │ ▒ │ static void vmx_complete_interrupts(struct vcpu_vmx *vmx) ▒ │ { ▒ │ mov %rsp,%rbp ▒ │ → callq __vmx_complete_interrupts.part.64 ▒ │ __vmx_complete_interrupts(&vmx->vcpu, vmx->idt_vectoring_info, ▒ │ pop %rbp ▒ │ ← retq ▒
GDB disassable: (gdb) disassemble /s vmx_complete_interrupts Dump of assembler code for function vmx_complete_interrupts: arch/x86/kvm/vmx.c: 8917 { 0x0000000000007110 <+0>: callq 0x7115 <vmx_complete_interrupts+5>
8918 __vmx_complete_interrupts(&vmx->vcpu, vmx->idt_vectoring_info, 0x0000000000007115 <+5>: mov 0x4590(%rdi),%esi
8873 vcpu->arch.nmi_injected = false; 0x000000000000711b <+11>: movb $0x0,0x32c8(%rdi)
arch/x86/kvm/x86.h: 14 vcpu->arch.exception.pending = false; 0x0000000000007122 <+18>: movb $0x0,0x1a7c(%rdi)
15 } 16 17 static inline void kvm_queue_interrupt(struct kvm_vcpu *vcpu, u8 vector, 18 bool soft) 19 { 20 vcpu->arch.interrupt.pending = true; 21 vcpu->arch.interrupt.soft = soft; 22 vcpu->arch.interrupt.nr = vector; 23 } 24 25 static inline void kvm_clear_interrupt_queue(struct kvm_vcpu *vcpu) 26 { 27 vcpu->arch.interrupt.pending = false; 0x0000000000007129 <+25>: movb $0x0,0x1a88(%rdi)
arch/x86/kvm/vmx.c: 8877 if (!idtv_info_valid) 0x0000000000007130 <+32>: test %esi,%esi 0x0000000000007132 <+34>: js 0x7135 <vmx_complete_interrupts+37>
8919 VM_EXIT_INSTRUCTION_LEN, 8920 IDT_VECTORING_ERROR_CODE); 8921 } 0x0000000000007134 <+36>: retq
8917 { 0x0000000000007135 <+37>: push %rbp 0x0000000000007136 <+38>: mov $0x440a,%ecx 0x000000000000713b <+43>: mov $0x440c,%edx ---Type <return> to continue, or q <return> to quit--- 0x0000000000007140 <+48>: mov %rsp,%rbp 0x0000000000007143 <+51>: callq 0x7000 <__vmx_complete_interrupts>
8919 VM_EXIT_INSTRUCTION_LEN, 8920 IDT_VECTORING_ERROR_CODE); 8921 }
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