powerd adaptive mode latching

Benjamin Lutz mail at maxlor.com
Thu Nov 8 15:20:36 PST 2007


On Thursday 08 November 2007 23:43:13 Simon Barner wrote:
> > > Please see kern/114722. The patch from the PR works fine with my
> > > T61 (T7300).
> > >
> > > Funny enough, I contacted re@ to get this into 7.0 only two
> > > minutes ago.
> > >
> > > For the archives, the similar bug described in bin/117375 already
> > > seems to be adressed in RELENG_7.
> >
> > both pr's are open .. and
> >
> > releng_7 and head are both at v 1.26 of acpi_perf.c
> >
> > so, no it's not fixed, *anywhere*.  :)
>
> It's true that both PRs are still open, but:
>
> 1) kern/114722 should fix your problem (CPUFREQ_CMP takes care of
> almost identical frequencies). Have you already had a chance to
> verify that?
>
> 2) bin/117375 talks about exactly identical frequencies, which should
> be handled by acpi_perf.c (1.26, line 303-306). However, the reporter
> (Cc'ed) of that PR runs FreeBSD 6.2-p8 which already contains the
> removal of duplicate entries (MFC from acpi_perf.c 1.24).
>
>    @Benjamin Lutz: Could you please check if the problem still
> exists, and if so, whether the patch from kern/114722 fixes it?

Before patch (still on 6.2-RELEASE-p8):
  dev.cpu.0.freq_levels: 2100/15000 2100/13720 1890/11360 1050/5531
So yes, the problem still exists.

After patch:
  dev.cpu.0.freq_levels: 2100/15000 2100/13720 1890/11360 1050/5531
And it seems the patch doesn't fix it.

Btw,  looking at that part (the for loop around line 303) of acpi_perf.c 
in isolation, it just occurred to me that the check for duplicate 
entries fails if the duplicate entries are the last in the list, which 
would probably prevent powerd from scaling the CPU back up. Or maybe 
I'm wrong, I haven't really looked at the rest of the code.

Thanks for working on this!

Cheers
Benjamin
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