cvs commit: src/sys/sys callout.h src/sys/kern kern_clock.c kern_intr.c kern_timeout.c

John Baldwin jhb at freebsd.org
Wed Apr 2 18:17:47 UTC 2008


On Wednesday 02 April 2008 07:20:30 am Jeff Roberson wrote:
> jeff        2008-04-02 11:20:30 UTC
>
>   FreeBSD src repository
>
>   Modified files:
>     sys/sys              callout.h
>     sys/kern             kern_clock.c kern_intr.c kern_timeout.c
>   Log:
>   Implement per-cpu callout threads, wheels, and locks.
>
>    - Move callout thread creation from kern_intr.c to kern_timeout.c
>    - Call callout_tick() on every processor via hardclock_cpu() rather than
>      inspecting callout internal details in kern_clock.c.
>    - Remove callout implementation details from callout.h
>    - Package up all of the global variables into a per-cpu callout
> structure. - Start one thread per-cpu.  Threads are not strictly bound. 
> They prefer to execute on the native cpu but may migrate temporarily if
> interrupts are starving callout processing.
>    - Run all callouts by default in the thread for cpu0 to maintain current
>      ordering and concurrency guarantees.  Many consumers may not properly
>      handle concurrent execution.
>    - The new callout_reset_on() api allows specifying a particular cpu to
>      execute the callout on.  This may migrate a callout to a new cpu.
>      callout_reset() schedules on the last assigned cpu while
>      callout_reset_curcpu() schedules on the current cpu.
>
>   Reviewed by:    phk
>   Sponsored by:   Nokia

This still has the bug in kern_intr.c:swi_add() as per previous e-mail.  
Surprised gcc didn't warn about it.

-- 
John Baldwin


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