Re: [PATCH v8 00/10] Hyper-V: paravirtualized remote TLB flushing and hypercall improvements

From: Stephen Hemminger
Date: Fri Jun 09 2017 - 12:14:59 EST


On Fri, 9 Jun 2017 15:27:26 +0200
Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> wrote:

> Changes since v7:
> - Minor code style fixes (drop explicit casting, reformat code a bit)
> in PATCH3 and PATCH9 [Andy Shevchenko]
>
> 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).
>
> Vitaly Kuznetsov (10):
> x86/hyper-v: include hyperv/ only when CONFIG_HYPERV is set
> x86/hyper-v: stash the max number of virtual/logical processor
> x86/hyper-v: make hv_do_hypercall() inline
> x86/hyper-v: fast hypercall implementation
> hyper-v: use fast hypercall for HVCALL_SIGNAL_EVENT
> x86/hyper-v: implement rep hypercalls
> hyper-v: globalize vp_index
> x86/hyper-v: use hypercall for remote TLB flush
> x86/hyper-v: support extended CPU ranges for TLB flush hypercalls
> tracing/hyper-v: trace hyperv_mmu_flush_tlb_others()
>
> MAINTAINERS | 1 +
> arch/x86/Kbuild | 2 +-
> arch/x86/hyperv/Makefile | 2 +-
> arch/x86/hyperv/hv_init.c | 90 ++++++------
> arch/x86/hyperv/mmu.c | 268 ++++++++++++++++++++++++++++++++++++
> arch/x86/include/asm/mshyperv.h | 148 +++++++++++++++++++-
> arch/x86/include/asm/trace/hyperv.h | 38 +++++
> arch/x86/include/uapi/asm/hyperv.h | 17 +++
> arch/x86/kernel/cpu/mshyperv.c | 13 +-
> drivers/hv/channel_mgmt.c | 20 +--
> drivers/hv/connection.c | 7 +-
> drivers/hv/hv.c | 9 --
> drivers/hv/hyperv_vmbus.h | 11 --
> drivers/hv/vmbus_drv.c | 17 ---
> drivers/pci/host/pci-hyperv.c | 10 +-
> include/linux/hyperv.h | 17 +--
> 16 files changed, 539 insertions(+), 131 deletions(-)
> create mode 100644 arch/x86/hyperv/mmu.c
> create mode 100644 arch/x86/include/asm/trace/hyperv.h
>

Looks good.

Reviewed-by: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>