By: Andrei F (andrei.delete@this.anandtech.com), September 14, 2021 1:07 am
Room: Moderated Discussions
Jukka Larja (roskakori2006.delete@this.gmail.com) on September 13, 2021 6:35 am wrote:
> Andrei F (andrei.delete@this.anandtech.com) on September 13, 2021 2:02 am wrote:
> > The point is that your window of user experience is 16/8ms. If the workload completes
> > interactively to fill that "QoS" at the current frequency without going over a utilisation
> > threshold in that sliding window, you *do not want to go any higher*.
> Unfortunately this doesn't work well for e.g. games, since at any given time it's hard to know
> how much performance is required during next "window of use experience". It's often possible
> to know, that nothing needs to be done until next vsync (which may be nearly 16 ms away), but
> it's hard to know how much performance is needed during that next 16 ms interval.
> > So your 120MHz FIVR is completely and utterly pointless. You would be wasting energy at higher
> > voltages for no gain in user performance. Fmax should only every be reached and triggered after
> > continuous load of 2-3x of user experience window - current mobile phones do that in around 40-50ms,
> > anything faster than that is waste of energy and battery life. These are not HW limitations, but
> > learning the hard way what the most efficient way to design battery powered DVFS logic.
> We once ported a game to pretty standard Android system. The CPU should have been more than good enough,
> but there was huge stuttering and missed frames. Turned out that it was too slow to speed up, and too agressive
> (in comparison) to slow down. By running a background thread busily doing nothing on one core, we got much
> more stable FPS (final solution was more sensible, but nothing you could call elegant).
> -JLarja

If this was several years ago, yes, some devices still shipped with naïve settings. This has been pretty much solved now in terms of load tracking algorithms.
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TopicPosted ByDate
alder lake.inteluser2021/09/10 02:52 AM
  alder lake.Andrei F2021/09/10 10:31 AM
    alder lake.Andrey2021/09/10 10:38 AM
      alder lake.rwessel2021/09/10 12:18 PM
      alder lake.Andrei F2021/09/10 01:49 PM
        alder lake.Andrey2021/09/10 05:12 PM
          alder lake.David Hess2021/09/10 08:39 PM
            alder lake.Andrey2021/09/11 01:28 AM
        alder lake.---2021/09/10 06:24 PM
          alder lake.Andrei F2021/09/12 02:09 AM
            DVFSDavid Kanter2021/09/12 10:58 PM
              DVFSAndrei F2021/09/13 02:02 AM
                DVFSAnon2021/09/13 04:28 AM
                DVFSJukka Larja2021/09/13 06:35 AM
                  DVFSAndrei F2021/09/14 01:07 AM
                    DVFSJukka Larja2021/09/14 05:11 AM
                      DVFSAndrei F2021/09/14 08:55 AM
                        DVFSJukka Larja2021/09/14 11:23 AM
                DVFS---2021/09/13 11:19 AM
                  DVFSDoug S2021/09/13 11:57 AM
                    DVFSDavid Hess2021/09/13 12:32 PM
                    DVFS---2021/09/13 02:06 PM
                      DVFSDavid Hess2021/09/13 03:21 PM
                    DVFSDavid Kanter2021/09/15 04:05 PM
                  DVFSDavid Hess2021/09/13 12:46 PM
                  DVFSJukka Larja2021/09/14 05:35 AM
                Quick shutdown?David Kanter2021/09/15 11:46 AM
                  Quick shutdown?Andrei F2021/09/16 08:12 AM
                    Quick shutdown?David Kanter2021/09/16 12:04 PM
                      Quick shutdown?Andrei F2021/09/17 02:35 AM
                        Quick shutdown?Andrei F2021/09/17 02:38 AM
            and weren't 'they' right?Daniel B2021/09/13 05:20 AM
              and weren't 'they' right?Andrei F2021/09/13 05:51 AM
                and weren't 'they' right?Daniel B2021/09/13 07:29 AM
              and weren't 'they' right?anon2021/09/13 06:07 AM
                and weren't 'they' right?Jukka Larja2021/09/13 06:26 AM
                  and weren't 'they' right?anon2021/09/14 12:37 AM
              Alder Lake has no little coresHeikki Kultala2021/09/13 07:33 AM
                Alder Lake has no little coresMichael S2021/09/13 08:33 AM
                  Alder Lake has no little coresme2021/09/13 11:45 AM
                  Alder Lake has no little coresHeikki Kultala2021/09/13 02:49 PM
                    Alder Lake has no little coresanon2021/09/14 12:42 AM
                why stop at two core sizes?hobold2021/09/14 06:47 AM
                  Memory caches did this, right?Mark Roulo2021/09/14 03:51 PM
                    Memory caches did this, right?Brett2021/09/14 08:17 PM
                      Memory caches did this, right?Kevin G2021/09/16 04:10 PM
                  Large reorder buffers (L1+L2)2021/09/15 12:24 PM
                    Large reorder buffers (L1+L2)hobold2021/09/15 01:06 PM
                Alder Lake has no little coresAdrian2021/09/14 09:33 AM
              and weren't 'they' right?David Hess2021/09/13 01:00 PM
                Battery vs PerformanceMark Roulo2021/09/13 01:18 PM
                  Battery vs PerformanceDoug S2021/09/13 03:05 PM
                    Battery vs PerformanceDavid Hess2021/09/13 03:28 PM
                      Battery vs Performance---2021/09/13 06:08 PM
                      Battery vs Performance---2021/09/13 06:08 PM
                      Battery vs PerformanceDoug S2021/09/13 09:53 PM
                    Battery vs PerformanceAnon2021/09/14 07:42 AM
                and weren't 'they' right?Daniel B2021/09/13 01:57 PM
                  and weren't 'they' right?David Hess2021/09/13 03:11 PM
                    and weren't 'they' right?---2021/09/13 03:38 PM
                  and weren't 'they' right?---2021/09/13 03:32 PM
                and weren't 'they' right?Brendan2021/09/14 04:30 AM
                  and weren't 'they' right?Jukka Larja2021/09/14 05:31 AM
              and weren't 'they' right?Etienne Lorrain2021/09/14 01:29 AM
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