https://bugzilla.kernel.org/show_bug.cgi?id=82211 --- Comment #1 from Zhou, Chao <chao.zhou@xxxxxxxxx> --- the first bad commit is: commit 6addfc42992be4b073c39137ecfdf4b2aa2d487f Author: Paolo Bonzini <pbonzini@xxxxxxxxxx> Date: Thu Mar 27 11:29:28 2014 +0100 KVM: x86: avoid useless set of KVM_REQ_EVENT after emulation Despite the provisions to emulate up to 130 consecutive instructions, in practice KVM will emulate just one before exiting handle_invalid_guest_state because x86_emulate_instruction always sets KVM_REQ_EVENT. However, we only need to do this if an interrupt could be injected, which happens a) if an interrupt shadow bit (STI or MOV SS) has gone away; b) if the interrupt flag has just been set (other instructions than STI can set it without enabling an interrupt shadow). This cuts another 700-900 cycles from the cost of emulating an instruction (measured on a Sandy Bridge Xeon: 1650-2600 cycles before the patch on kvm-unit-tests, 925-1700 afterwards). Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> -- You are receiving this mail because: You are watching the assignee of the bug. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
