:Hi,
:
:Attached is a patch that changes a few things:
:
:1) Removes the CVS ID; that was vestigial, I forgot I'd included that.
:
:2) Rename idlezero_count back to cnt_prezero; this is because this is the
:original name (in FreeBSD and in DragonFly). I don't feel strongly about
:this at all - is it reasonable to try to match up sysctl names or not
:worth it?
Since it isn't part of the primary vmstats structure, no. It's better
to keep it categorized with the other idlezero sysctls.
:3) Change vm_page_zero_check() to return the reason that the check failed.
Well, I think a better solution here would be to just do a separate
check to calculate the tsleep time and not try to build it into
vm_page_zero_check(). Or, alternatively, have vm_page_zero_check()
return the tsleep time (where a value of 0 indicates that page zeroing
should occur).
:4) In vm_pagezero(), switch tsleep to sleep for a variable amount of time;
:by default it is still hz/10, now called DEFAULT_SLEEP_TIME. If
:vm_page_zero_check() failed because zeroing was either disabled or because
:we hit the ZIDLE_HI limit, mark ourselves to sleep for a long time
:(hz*10). If we are lower than the upper limit by higher than the low
:limit, or we are below the low limit, restore the sleep time.
The concept is fine. The implementation is a bit complex for what
it does.
:5) Set zero_state when we hit the high mark and clear when we fall below
:the low mark; this restores the hysteresis formerly present.
Yes, I noticed the hysteresis seemed to be off. Instead of using
a separate variable here you can integrate the hysteresis state into
the primary state. e.g. STATE_IDLE_LO, STATE_IDLE_HI.
:Other thoughts - before we enter the mainloop, perhaps a sleep without a
:timeout, if idlezero_enable = 0? Then the enable/disable sysctl could be a
:SYSCTL_PROC which wakes it up; this would minimize the (admittedly tiny)
:load on systems on which it is disabled.
:...
:Thoughts on any of this?
:
:Thanks,
:-- vs
No, this isn't necessary. Nobody is going to notice a few microseconds
during the boot sequence.
-Matt
