Re: [PATCH, v10 3/3] cgroups: introduce timer slack controller

From
Peter Zijlstra <peterz@infradead.org>
Date
2011-10-17 14:49:57
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Reply to
Matthew Garrett, 2011-10-17
On Mon, 2011-10-17 at 15:40 +0100, Matthew Garrett wrote:
On Mon, Oct 17, 2011 at 04:28:27PM +0200, Peter Zijlstra wrote:
quoted
On Mon, 2011-10-17 at 15:11 +0100, Matthew Garrett wrote:
quoted
Whether or not you want the animation to carry on animating is policy, 
and you need something to be the policy agent. Let's say firefox is 
invisible. I now grab a copy of its window contents. What do I get?
An XDamage and repaint from the X client, after which your copy will
complete and you get what you asked for?
An XDamage and then an asynchronous RPC call to the remote server to 
identify the contents of the next frame before drawing them, plus some 
sort of new synchronisation mechanism for blocking the X query until 
that point?
Why would this be a problem? 

I mean, why would getting a copy of an otherwise invisible surface be a
performance sensitive path? If the compositor needs the surface it would
make it visible and send the XDamage once and keep it visible henceforth
until the time it again becomes invisible, at which point you have to
stop updates again.

The normal case is where things are visible and things are kept
up-to-date, that doesn't change.
quoted
quoted
 in preference to merging a piece 
of code that's functionally consistent with the rest of the cgroups 
infrastructure?
Yep.. because as of yet there isn't a sane use-case to warrant adding
the maintenance burden. Any cgroup controller is functionally
consistent, per definition, that doesn't make it useful or even sane.
Timers are a resource. People want to manage that resource. cgroups are 
a convenient mechanism for managing resources.
Yes, and a ball is round (unless you're a USA-ian, in which case they're
ovoid), what's your point?
Thread (35 messages) 35 messages, 8 authors, last reply 2011-10-17
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