Re: idle waste
Re: idle waste
- Subject: Re: idle waste
- From: "Timothy J. Wood" <email@hidden>
- Date: Thu, 28 Mar 2002 14:20:22 -0800
On Thursday, March 28, 2002, at 12:07 PM, Paul Cezanne wrote:
If I have a Cocoa application just sitting there doing nothing, how
much CPU time does it waste? A lot, some, not much, negligible?
None, assuming the Mach thread scheduler doesn't get broken. When an
application is idle, it is blocked waiting for a message from the
kernel. This puts its thread on a wait queue and it shouldn't get run
again until the resource it is waiting on (a Mach port) is tickled.
I essentially need to write a UNIX daemon and would rather do it in
Cocoa since it has to have some minimal UI, but it will be running all
the time.
This won't work if you want your code to run while no one is logged in
or if you want your code to start as part of the system startup.
Instead, you should split your code into a proper daemon and a GUI app
to manage the daemon.
Bonus question: Does the amount wasted change if I have a window with
controls in it open?
It can. If you have a progress view, a default button (so the Aqua UI
code is throbbing it) or any other control that wants to draw itself.
As long as none of your controls are updating, then, no, there is no
additional CPU time expense.
-tim
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| References: | |
| | >idle waste (From: Paul Cezanne <email@hidden>) |