Skip to content
GitLab
Projects Groups Topics Snippets
  • /
  • Help
    • Help
    • Support
    • Community forum
    • Submit feedback
  • Register
  • Sign in
  • L linux
  • Project information
    • Project information
    • Activity
    • Labels
    • Members
  • Repository
    • Repository
    • Files
    • Commits
    • Branches
    • Tags
    • Contributor statistics
    • Graph
    • Compare revisions
  • Issues 0
    • Issues 0
    • List
    • Boards
    • Service Desk
    • Milestones
  • Merge requests 0
    • Merge requests 0
  • Deployments
    • Deployments
    • Releases
  • Monitor
    • Monitor
    • Incidents
  • Analytics
    • Analytics
    • Value stream
    • Repository
  • Wiki
    • Wiki
  • Snippets
    • Snippets
  • Activity
  • Graph
  • Create a new issue
  • Commits
  • Issue Boards
Collapse sidebar
  • Kirill Smelkov
  • linux
  • Repository
  • linux
  • drivers
  • clocksource
  • hyperv_timer.c
Find file BlameHistoryPermalink
  • Vitaly Kuznetsov's avatar
    clocksource/drivers/hyperv: Enable TSC page clocksource on 32bit · 3e2d9453
    Vitaly Kuznetsov authored Aug 22, 2019
    
    
    There is no particular reason to not enable TSC page clocksource on
    32-bit. mul_u64_u64_shr() is available and despite the increased
    computational complexity (compared to 64bit) TSC page is still a huge win
    compared to MSR-based clocksource.
    
    In-kernel reads:
      MSR based clocksource: 3361 cycles
      TSC page clocksource: 49 cycles
    
    Reads from userspace (utilizing vDSO in case of TSC page):
      MSR based clocksource: 5664 cycles
      TSC page clocksource: 131 cycles
    
    Enabling TSC page on 32bits allows to get rid of CONFIG_HYPERV_TSCPAGE as
    it is now not any different from CONFIG_HYPERV_TIMER.
    
    Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
    Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
    Link: https://lkml.kernel.org/r/20190822083630.17059-1-vkuznets@redhat.com
    3e2d9453
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7