Messages in this thread | | | Date | Wed, 10 Feb 2010 07:43:03 +0530 | From | Arun R Bharadwaj <> | Subject | Re: [v11 PATCH 1/9]: cpuidle: Design documentation patch |
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* Randy Dunlap <rdunlap@xenotime.net> [2010-02-09 09:00:54]:
> On 02/09/10 00:29, Arun R Bharadwaj wrote: > > * Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2010-02-09 13:58:16]: > > > > This patch adds a little information about the redesigned cpuidle > > infrastructure in Documentation/cpuidle/core.txt > > > > Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com> > > --- > > Documentation/cpuidle/core.txt | 35 +++++++++++++++++++++++++++++++++++ > > 1 file changed, 35 insertions(+) > > > > Index: linux.trees.git/Documentation/cpuidle/core.txt > > =================================================================== > > --- linux.trees.git.orig/Documentation/cpuidle/core.txt > > +++ linux.trees.git/Documentation/cpuidle/core.txt > > @@ -21,3 +21,38 @@ which can be used to switch governors at > > is meant for developer testing only. In normal usage, kernel picks the > > best governor based on governor ratings. > > SEE ALSO: sysfs.txt in this directory. > > + > > +Design: > > + > > +Cpuidle allows for registration of multiple sets of idle routines. > > +The latest registered set is used by cpuidle governors as the current > > +active set to choose the right idle state. This set is managed as a > > +list and each time the newly registered set is added to the head of the > > +list and made the current active set. > > + > > +An example of how this would work on x86 is shown below. > > + > +----------------- ----------------- > +| | | | > +| choose b/w | mwait is chosen | mwait | > +| mwait, poll, |-------------------------------------> |(current active| > +| default, c1e | register to cpuidle | set) | > +| | with mwait as the idle routine | | > +----------------- ----------------- > > What is "b/w" above? "between"? I've see "btw" used a few times as an > abbreviation for between, but I don't recall ever seeing b/w. > OTOH, I have seen b/w used for bandwidth. >
Here, it means between. Will remove the abbreviation since it might be confusing.
> > > + > > + > > +----------------- ----------------- > > +| | | c1, c2, c3 | > > +| ACPI | register to cpuidle | (current) | > > +| discovery |-------------------------------------> |---------------| > > +| | with c1, c2, c3 | mwait | > > +| | as set of idle routines | | > > +----------------- ----------------- > > + > > +With this mechanism, a module can register and unregister its set of > > +idle routines at run time in a clean manner. > > + > > +The main idle routine called inside cpu_idle() of every arch is defined in > > +driver/cpuidle/cpuidle.c which would in turn call the idle routine selected > > drivers/ >
noted.
thanks arun
> > +by the governor. If the CONFIG_CPU_IDLE is disabled, the arch needs to > > +provide an alternate definition for cpuidle_idle_call(). > > > -- > ~Randy
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