Uploaded image for project: 'JDK'
  1. JDK
  2. JDK-7082553

Interpret Thread.setPriority(Thread.MAX_PRIORITY) to mean FX60 on Solaris 10 and 11

    Details

    • Type: Enhancement
    • Status: Closed
    • Priority: P2
    • Resolution: Fixed
    • Affects Version/s: hs22, 7u2
    • Fix Version/s: hs23
    • Component/s: hotspot
    • Labels:
    • Subcomponent:
    • Resolved In Build:
      b12
    • CPU:
      generic, unknown
    • OS:
      solaris
    • Verification:
      Verified

      Backports

        Description

        See Comments.
        A SPARC T4 processor can run in either multi- or single-thread mode. In multi-thread
        mode, core resources are shared by 8 threads, but in single-thread mode all core
        resources are dedicated to a single thread, resulting in much higher performance
        for that single thread relative to running it in multi-thread mode.

        The default Solaris time-sharing scheduler is biased toward maximum use of hardware
        resources by as many LWPs as possible, which means that multi-thread mode is the
        default. To use T4's single-thread mode effectively, the scheduler must know which
        LWP(s) should run in that mode. Solaris 10u10 and 11 will do their best to
        give LWPs running at priority 60 in the FX scheduling class exclusive use of
        a T4 core, thus running the LWP in single-thread mode.

        We'd like Java applications that require fast per-thread response time to run in
        the FX60 scheduling class. One way to do so is to use Thread.setPriority(Thread.
        MAX_PRIORITY) as a directive to use FX60 for that thread when running on a T4 and
        S10u10/S11. This is a change from current practice, which maps the available Java
        thread priorities evenly across the 60 (0-59) Solaris time sharing priorities.
        We don't expect that to be a problem, however, since the proposed change will
        apply only to T4, which is new hardware. Note that this CR uses "unknown" for
        the Hardware field: T4 is not yet available as a Hardware option in bugster.

          Attachments

            Issue Links

              Activity

                People

                • Assignee:
                  phh Paul Hohensee
                  Reporter:
                  phh Paul Hohensee
                • Votes:
                  0 Vote for this issue
                  Watchers:
                  2 Start watching this issue

                  Dates

                  • Created:
                    Updated:
                    Resolved:
                    Imported:
                    Indexed: