RE: [PATCH v2 00/10] Hyper-V: praravirtualized remote TLB flushing and hypercall improvements

[KY Srinivasan]

> -----Original Message-----
> From: Vitaly Kuznetsov [mailto:vkuznets@xxxxxxxxxx]
> Sent: Wednesday, April 12, 2017 3:43 AM
> To: devel@xxxxxxxxxxxxxxxxxxxxxx; x86@xxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx; KY Srinivasan <kys@xxxxxxxxxxxxx>;
> Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>; Stephen Hemminger
> <sthemmin@xxxxxxxxxxxxx>; Thomas Gleixner <tglx@xxxxxxxxxxxxx>; Ingo
> Molnar <mingo@xxxxxxxxxx>; H. Peter Anvin <hpa@xxxxxxxxx>; Steven
> Rostedt <rostedt@xxxxxxxxxxx>; Jork Loeser
> <Jork.Loeser@xxxxxxxxxxxxx>; Simon Xiao <sixiao@xxxxxxxxxxxxx>
> Subject: [PATCH v2 00/10] Hyper-V: praravirtualized remote TLB flushing and
> hypercall improvements
> 
> Changes since v1:
> - Add a patch to build code in arch/x86/hyperv/ only when CONFIG_HYPERV
> is
>   set.
> - Add a patch to get maximum virtual/logical processor on Hyper-V.
> - Add additional clobbers to hypercalls [Jork Loeser]
> - Add variable header size support to rep hypercalls.
> - Rename vmbus_cpu_number_to_vp_number ->
> hv_cpu_number_to_vp_number
>   [K. Y. Srinivasan]
> - Remove spinlocks from hyperv_flush_tlb_others() [Jork Loeser]
> - Account for mm==NULL in hyperv_flush_tlb_others() [Simon Xiao]
> - Add support for HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX/LIST_EX
> hypercalls
>   to support >64 vCPUs [K. Y. Srinivasan, Jork Loeser]
> - Move hyperv.h to arch-specific place [Steven Rostedt]
> - Rebased to the latest char-misc-next tree.
> 
> Original descriptions:
> 
> 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	3m44.994s
> user	0m3.829s
> sys	3m36.323s
> 
> After:
> # time ./pthread_mmap ./randfile
> real	2m57.145s
> user	0m3.797s
> sys	2m34.812s
> 
> 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()

Thanks Vitaly; we have tested these patches on various platforms of interest.

Acked-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
Tested-by: Simon Xiao <sixiao@xxxxxxxxxxxxx>
Tested-by: Srikanth Myakam <v-srm@xxxxxxxxxxxxx>

Regards,

K. Y
> 
>  MAINTAINERS                         |   1 +
>  arch/x86/Kbuild                     |   4 +-
>  arch/x86/hyperv/Makefile            |   2 +-
>  arch/x86/hyperv/hv_init.c           |  90 ++++++------
>  arch/x86/hyperv/mmu.c               | 270
> ++++++++++++++++++++++++++++++++++++
>  arch/x86/include/asm/mshyperv.h     | 148 +++++++++++++++++++-
>  arch/x86/include/asm/trace/hyperv.h |  34 +++++
>  arch/x86/include/uapi/asm/hyperv.h  |  36 +++++
>  arch/x86/kernel/cpu/mshyperv.c      |  14 +-
>  drivers/hv/channel_mgmt.c           |  22 ++-
>  drivers/hv/connection.c             |   8 +-
>  drivers/hv/hv.c                     |   9 --
>  drivers/hv/hyperv_vmbus.h           |  11 --
>  drivers/hv/vmbus_drv.c              |  17 ---
>  drivers/pci/host/pci-hyperv.c       |   4 +-
>  include/linux/hyperv.h              |  21 ++-
>  16 files changed, 567 insertions(+), 124 deletions(-)
>  create mode 100644 arch/x86/hyperv/mmu.c
>  create mode 100644 arch/x86/include/asm/trace/hyperv.h
> 
> --
> 2.9.3