[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v5 0/2] x86/kvm: Reduce vcpu_is_preempted() overhead
v4->v5: - As suggested by PeterZ, use the asm-offsets header file generation mechanism to get the offset of the preempted field in kvm_steal_time instead of hardcoding it. v3->v4: - Fix x86-32 build error. v2->v3: - Provide an optimized __raw_callee_save___kvm_vcpu_is_preempted() in assembly as suggested by PeterZ. - Add a new patch to change vcpu_is_preempted() argument type to long to ease the writing of the assembly code. v1->v2: - Rerun the fio test on a different system on both bare-metal and a KVM guest. Both sockets were utilized in this test. - The commit log was updated with new performance numbers, but the patch wasn't changed. - Drop patch 2. As it was found that the overhead of callee-save vcpu_is_preempted() can have some impact on system performance on a VM guest, especially of x86-64 guest, this patch set intends to reduce this performance overhead by replacing the C __kvm_vcpu_is_preempted() function by an optimized version of __raw_callee_save___kvm_vcpu_is_preempted() written in assembly. Waiman Long (2): x86/paravirt: Change vcp_is_preempted() arg type to long x86/kvm: Provide optimized version of vcpu_is_preempted() for x86-64 arch/x86/include/asm/paravirt.h | 2 +- arch/x86/include/asm/qspinlock.h | 2 +- arch/x86/kernel/asm-offsets_64.c | 9 +++++++++ arch/x86/kernel/kvm.c | 26 +++++++++++++++++++++++++- arch/x86/kernel/paravirt-spinlocks.c | 2 +- 5 files changed, 37 insertions(+), 4 deletions(-) -- 1.8.3.1 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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