Re: low-latency scheduling patch for 2.4.0

[Andrew Morton]

Andrew Morton wrote:
> 
> A patch against kernel 2.4.0 final which provides low-latency
> scheduling is at
> 
>         http://www.uow.edu.au/~andrewm/linux/schedlat.html#downloads
> 

This has been updated for 2.4.1-pre3

- Fixed latency problems with some /proc files and forking
  when many files are open.

- Fixed the tcp-minisocks thing.

- The patch now works properly on SMP.

  If a wakeup is directed to a SCHED_FIFO or SCHED_RR
  task then we request a reschedule on *all* non-idle
  CPUs.

  This causes any CPU which is holding a long-lived
  spinlock to bale out, allowing the target CPU to
  acquire the spinlock and then reschedule normally.

  Bit of a hack, but it works very well and there
  is no impact on the system unless there are
  non-SCHED_OTHER tasks running.

  Five lines of code :)