linux-kernel - RE: [PATCH 0/7] Hyper-V: praravirtualized remote TLB flushing and hypercall improvements

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Date:   Sat, 8 Apr 2017 14:57:11 +0000
From:   KY Srinivasan <kys@...rosoft.com>
To:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        "devel@...uxdriverproject.org" <devel@...uxdriverproject.org>,
        "x86@...nel.org" <x86@...nel.org>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Haiyang Zhang" <haiyangz@...rosoft.com>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        "Jork Loeser" <Jork.Loeser@...rosoft.com>
Subject: RE: [PATCH 0/7] Hyper-V: praravirtualized remote TLB flushing and
 hypercall improvements



> -----Original Message-----
> From: Vitaly Kuznetsov [mailto:vkuznets@...hat.com]
> Sent: Friday, April 7, 2017 4:27 AM
> To: devel@...uxdriverproject.org; x86@...nel.org
> Cc: linux-kernel@...r.kernel.org; KY Srinivasan <kys@...rosoft.com>;
> Haiyang Zhang <haiyangz@...rosoft.com>; Stephen Hemminger
> <sthemmin@...rosoft.com>; Thomas Gleixner <tglx@...utronix.de>; Ingo
> Molnar <mingo@...hat.com>; H. Peter Anvin <hpa@...or.com>; Steven
> Rostedt <rostedt@...dmis.org>; Jork Loeser <Jork.Loeser@...rosoft.com>
> Subject: [PATCH 0/7] Hyper-V: praravirtualized remote TLB flushing and
> hypercall improvements
> 
> Hi,
> 
> 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).

Thanks Vitaly. We are currently testing these patches on Azure and other Hyper-V
platforms and will report back.

K. Y 
> 
> Vitaly Kuznetsov (7):
>   x86/hyperv: make hv_do_hypercall() inline
>   x86/hyper-v: fast hypercall implementation
>   hyper-v: use fast hypercall for HVCALL_SIGNAL_EVENT
>   x86/hyperv: implement rep hypercalls
>   hyper-v: globalize vp_index
>   x86/hyper-v: use hypercall for remove TLB flush
>   tracing/hyper-v: trace hyperv_mmu_flush_tlb_others()
> 
>  MAINTAINERS                        |   1 +
>  arch/x86/hyperv/Makefile           |   2 +-
>  arch/x86/hyperv/hv_init.c          |  90 +++++++++++--------------
>  arch/x86/hyperv/mmu.c              | 134
> +++++++++++++++++++++++++++++++++++++
>  arch/x86/include/asm/mshyperv.h    | 131
> ++++++++++++++++++++++++++++++++++++
>  arch/x86/include/uapi/asm/hyperv.h |  26 +++++++
>  arch/x86/kernel/cpu/mshyperv.c     |   1 +
>  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 -----
>  include/linux/hyperv.h             |  21 +++---
>  include/trace/events/hyperv.h      |  30 +++++++++
>  14 files changed, 386 insertions(+), 117 deletions(-)
>  create mode 100644 arch/x86/hyperv/mmu.c
>  create mode 100644 include/trace/events/hyperv.h
> 
> --
> 2.9.3