Wanpeng Li <kernellwp@xxxxxxxxx> writes: > 2017-11-06 17:14 GMT+08:00 Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>: >> Wanpeng Li <kernellwp@xxxxxxxxx> writes: >> >>> 2017-08-03 0:09 GMT+08:00 Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>: >>>> Changes since v9: >>>> - Rebase to 4.13-rc3. >>>> - Drop PATCH1 as it was already taken by Greg to char-misc tree. There're no >>>> functional dependencies on this patch so the series can go through a different tree >>>> (and it actually belongs to x86 if I got Ingo's comment right). >>>> - Add in missing void return type in PATCH1 [Colin King, Ingo Molnar, Greg KH] >>>> - A few minor fixes in what is now PATCH7: add pr_fmt, tiny style fix in >>>> hyperv_flush_tlb_others() [Andy Shevchenko] >>>> - Fix "error: implicit declaration of function 'virt_to_phys'" in PATCH2 >>>> reported by kbuild test robot (#include <asm/io.h>) >>>> - Add Steven's 'Reviewed-by:' to PATCH9. >>>> >>>> Original description: >>>> >>>> Hyper-V supports hypercalls for doing local and remote TLB flushing and >>>> gives its guests hints when using hypercall is preferred. While doing >>>> hypercalls for local TLB flushes is probably not practical (and is not >>>> being suggested by modern Hyper-V versions) remote TLB flush with a >>>> hypercall brings significant improvement. >>>> >>>> To test the series I wrote a special 'TLB trasher': on a 16 vCPU guest I >>>> was creating 32 threads which were doing 100000 mmap/munmaps each on some >>>> big file. Here are the results: >>>> >>>> Before: >>>> # time ./pthread_mmap ./randfile >>>> real 3m33.118s >>>> user 0m3.698s >>>> sys 3m16.624s >>>> >>>> After: >>>> # time ./pthread_mmap ./randfile >>>> real 2m19.920s >>>> user 0m2.662s >>>> sys 2m9.948s >>>> >>>> This series brings a number of small improvements along the way: fast >>>> hypercall implementation and using it for event signaling, rep hypercalls >>>> implementation, hyperv tracing subsystem (which only traces the newly added >>>> remote TLB flush for now). >>>> >>> >>> Hi Vitaly, >>> >>> Could you attach your benchmark? I'm interested in to try the >>> implementation in paravirt kvm. >>> >> >> Oh, this would be cool) I briefly discussed the idea with Radim (one of >> KVM maintainers) during the last KVM Forum and he wasn't opposed to the >> idea. Need to talk to Paolo too. Good thing is that we have everything > > I talk with Paolo today and he points this feature to me, so I believe > he likes it. :) In addition, > https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/reference/tlfs > I search Hypervisor Top Level Functional Specification v5.0b.pdf > document but didn't find a section introduce the Hyper-V: > paravirtualized remote TLB flushing and hypercall stuff, could you > point out? > It's there, search for HvFlushVirtualAddressSpace/HvFlushVirtualAddressSpaceEx and HvFlushVirtualAddressList/HvFlushVirtualAddressListEx. -- Vitaly
