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Date:      Thu, 11 May 2017 18:01:26 +0000
From:      bugzilla-noreply@freebsd.org
To:        freebsd-bugs@FreeBSD.org
Subject:   [Bug 219213] powerd causing problems with ryzen
Message-ID:  <bug-219213-8-nSBpUd3orz@https.bugs.freebsd.org/bugzilla/>
In-Reply-To: <bug-219213-8@https.bugs.freebsd.org/bugzilla/>
References:  <bug-219213-8@https.bugs.freebsd.org/bugzilla/>

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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D219213

--- Comment #1 from SF <shitman71@hotmail.com> ---
To be more specific about power-saving features:

CPU's have different p-states since a long time now but powerd only knows 3
options to set:

adaptive, maximum, minimum

I have only 2 options for the adaptive-mode to set percentages for minimum =
and
maximum.

I dont know how many different p-state each CPU has but there is definitely
more then just maximum and minimum. I remember 4-5 different p-states with =
my
old Phenom X6 1100T(cpu from 2010) i had before.

Your powerd is very primitive and i think it doesnt fit todays demands of
flexible power-management and accurate delivery of performance.

With 4-5 p-states i can set 4-5 barriers to hit to get my CPU more precisely
onto its needed level.

With todays CPU-Performance i can do more math to calculate its needed p-st=
ate.
An Ryzen R7 1700X has 16 CPU-Cores, there is easyly some spare
calculation-power to do the math for adjusting the p-states more accurate.

e.x.:
1 primary interval(long time period)
1 secondary interval(short time period) which gets launched from the primary
interval after the specified time
1 counter for each p-state-limit

The primvary interval kicks in each 15 seconds.
The secondary interval checks every 40ms the average cpu-load for an durati=
on
of 1 second. It increases the counter for the assigned p-state at each check
until the 1 second duration is finished.

It selects the p-state with the highest counter and priority.

Shouldn't be too hard?

--=20
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