Re: Power consumption HZ100, HZ250, HZ1000: new numbers

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



David Weinehall wrote:
On Sun, Jul 31, 2005 at 07:23:54PM -0400, Lee Revell wrote:
Any idea what their official recommendation for people running apps that
require the 1ms sleep resolution is?  Something along the lines of "Get
bent"?

Calm down.

Yes, Lee needs to chill a bit. I'll hopefully explain our position calmly enough below.

Any argument along the lines of the change of a default
value in the defconfig screwing people over equally applies the other
way around; by not changing the defconfig, you're screwing laptop users
(and others that want less power consumption) over.  The world is not
black and white, it's a very boring gray (or a very sadening bloody
red; but I hope we won't come to that point just because of a silly
argument on lkml...)

The tradeoff is a realistic 4.4% power savings vs a 300% increase in the minimum sleep period. A user will see zero power savings if they have a USB mouse (probably 99% of desktops). On top of that, we can throw in Con's disturbing AV benchmark results (1). As a result, some of us don't think 250HZ is a great tradeoff to make _for_the_default_value_.

(1) http://article.gmane.org/gmane.linux.kernel/319124/

In the end, Linus will decide this anyway.  I can understand that you
don't want to change your application.  Help developing the dynamic
tick patch, and maybe you won't have to =)

From what I can tell, tick skipping works fine right now, it just needs some cleanup. Thus I'd expect something like it will get integrated into 2.6.14. If it gets in, the default HZ should go back up to 1000. In that case why decrease it for exactly one patchlevel?

As an app programmer, it'd be nice not to have to support 2.6.13 differently from 2.6.(x!=13). For my app, busy waiting means a ~12% load increase for 2.6.13 compared to (probably) all other 2.6 kernel versions. That's certainly violating the principle of least surprise. Up to now, it was easy enough to tell people "upgrade from 2.4.x and it'll work better". Now it gets more complicated.

Finally, as a conspiracy theorist, I wonder if Linus is just playing us to get more people working on the tick skipping and highres timer patches. Someone with the ability to herd cats obviously has to be sneaky. As an impressive demonstration of my free will I'm going to go test dyntick on my VIA Epia board...

 - Jim Bruce
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]
  Powered by Linux