>From http://lwn.net/Articles/463357/

The "timer slack controller" is a proposed mechanism that would allow
a session management program to adjust the timer tolerances of a group
of processes with a single knob. It seems like a relatively obscure
and harmless feature, but it has been the focus of an intense debate
on the kernel mailing lists. The core question has been seen before:
what measures should the kernel take, if any, to keep poorly-written
applications from hurting performance?

Timers allow a process to request a wakeup at some future time; timer
slack gives the kernel some leeway in its implementation of those
timers. If the kernel can delay specific timers by a bounded amount,
it can often expire multiple timers at once, minimizing the number of
wakeups and, thus, reducing the system's power consumption. Some
processes need more precise timing than others; for this reason, the
kernel allows a process to specify its maximum timer slack with the
prctl() system call. There is, currently, no mechanism to allow one
process to adjust another process's timer slack value; it is generally
assumed that any given process knows best when it comes to its own
timing requirements.

The timer slack controller allows a suitably privileged process to set
the timer slack value for every process contained within a control
group. The patch has been circulating for some time without generating
a great deal of interest; it recently resurfaced in response to the
"plumber's wish list for Linux" which requested such a feature.
.............
______________________________________


Best

A. Mani



-- 
A. Mani
CU, ASL, CLC,  AMS, CMS
http://www.logicamani.co.cc

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