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

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Message-Id: <20170407112701.17157-1-vkuznets@redhat.com>
Date:   Fri,  7 Apr 2017 13:26:54 +0200
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     devel@...uxdriverproject.org, x86@...nel.org
Cc:     linux-kernel@...r.kernel.org,
        "K. Y. 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).

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

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2.9.3