#119 IA64 perfctr profiling clashes with broken firmware

closed-wont-fix
nobody
None
6
2006-01-22
2004-04-08
John Levon
No

Some IA64 systems have broken firmware that do not
behave correctly when using CONFIG_IA64_PAL_IDLE. It
must be disabled.

We should probably depend on !CONFIG_IA64_PAL_IDLE.

Discussion

  • John Levon

    John Levon - 2006-01-22

    Logged In: YES
    user_id=53034

    This is an issue with the firmware, not with us.

     
  • John Levon

    John Levon - 2006-01-22
    • status: open --> closed-wont-fix
     
  • Nobody/Anonymous

    Logged In: NO

    On some firmware versions, there is a problem with
    the idle loop goes into low power mode via a PAL call.
    Some events are frozen while others keep on counting
    which results is inconsistent results. More recent
    versions of the kernel have a workaround when perfmon
    or Oprofile is active.

    Basically, the machine does not call into PAL as soon as a
    perfmon context is being attached to a thread or processor.
    I think this work around is in RHEL4/SLES9. You can look
    at arch/ia64/kernel/process.c and for symbol
    update_pal_halt_status().

    On other kernels, you may either:
    - and the boot cmdline pass the "nohalt" option
    - recompile kernel without CONFIG_IA64_PAL_IDLE disabled

     

Get latest updates about Open Source Projects, Conferences and News.

Sign up for the SourceForge newsletter:





No, thanks