Hi, > -----Original Message----- > From: Shameerali Kolothum Thodi > Sent: 06 May 2021 17:52 > To: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; kvmarm@xxxxxxxxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx > Cc: maz@xxxxxxxxxx; will@xxxxxxxxxx; catalin.marinas@xxxxxxx; > james.morse@xxxxxxx; julien.thierry.kdev@xxxxxxxxx; > suzuki.poulose@xxxxxxx; jean-philippe@xxxxxxxxxx; Linuxarm > <linuxarm@xxxxxxxxxx> > Subject: [RFC PATCH 0/3] kvm/arm: New VMID allocator based on asid(2nd > approach) > > This is based on a suggestion from Will [0] to try out the asid > based kvm vmid solution as a separate VMID allocator instead of > the shared lib approach attempted in v4[1]. > > The idea is to compare both the approaches and see whether the > shared lib solution with callbacks make sense or not. A gentle ping on this. Please take a look and let me know. Thanks, Shameer > Though we are not yet using the pinned vmids yet, patch #2 has > code for pinned vmid support. This is just to help the comparison. > > Test Setup/Results > ---------------- > The measurement was made with maxcpus set to 8 and with the > number of VMID limited to 4-bit. The test involves running > concurrently 40 guests with 2 vCPUs. Each guest will then > execute hackbench 5 times before exiting. > > The performance difference between the current algo and the > new one are(avg. of 10 runs): > - 1.9% less entry/exit from the guest > - 0.5% faster > This is more or less comparable to v4 numbers. > > For the complete series, please see, > https://github.com/hisilicon/kernel-dev/tree/private-v5.12-rc7-vmid-2nd-rfc > > and for the shared asid lib v4 solution, > https://github.com/hisilicon/kernel-dev/tree/private-v5.12-rc7-asid-v4 > > As you can see there are of course code duplication with this > approach but may be this one is more easy to maintain considering > the complexity involved. > > Please take a look and let me know your feedback. > > Thanks, > Shameer > > > [0] https://lore.kernel.org/lkml/20210422160846.GB2214@willie-the-truck/ > [1] > https://lore.kernel.org/lkml/20210414112312.13704-1-shameerali.kolothum.t > hodi@xxxxxxxxxx/ > > Julien Grall (2): > arch/arm64: Introduce a capability to tell whether 16-bit VMID is > available > kvm/arm: Align the VMID allocation with the arm64 ASID one > > Shameer Kolothum (1): > kvm/arm: Introduce a new vmid allocator for KVM > > arch/arm64/include/asm/cpucaps.h | 3 +- > arch/arm64/include/asm/kvm_asm.h | 4 +- > arch/arm64/include/asm/kvm_host.h | 11 +- > arch/arm64/include/asm/kvm_mmu.h | 7 +- > arch/arm64/kernel/cpufeature.c | 9 + > arch/arm64/kvm/Makefile | 2 +- > arch/arm64/kvm/arm.c | 115 ++++-------- > arch/arm64/kvm/hyp/nvhe/hyp-main.c | 6 +- > arch/arm64/kvm/hyp/nvhe/tlb.c | 10 +- > arch/arm64/kvm/hyp/vhe/tlb.c | 10 +- > arch/arm64/kvm/mmu.c | 1 - > arch/arm64/kvm/vmid.c | 285 > +++++++++++++++++++++++++++++ > 12 files changed, 354 insertions(+), 109 deletions(-) > create mode 100644 arch/arm64/kvm/vmid.c > > -- > 2.17.1 _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
