MISER(5)MISER(5)NAME
miser, batch - The Miser Resource Manager
DESCRIPTION
Miser is a resource management facility with a batch process scheduling
component. This component allows a system administrator to balance
interactive and batch load on a machine without static partitioning.
Miser provides deterministic batch scheduling associated with static
partitioning without the wasted resources that result from static
partitioning. Idle resources are always available for use regardless of
ownership, but are reclaimed on demand as necessary.
Miser schedules applications with known time and space requirements. The
user level component of miser, the daemon, generates a non-conflicting
schedule of applications. The schedule is said to be non-conflicting
because at no point in the schedule are the resources over-subscribed. An
application scheduled by miser is scheduled to begin running at a
particular point in time and then to run without preemption until the end
time has been reached. The kernel component uses the schedule to
determine what resources an application has access to and when to
actually schedule an application to run. The applications are said to be
scheduled in a batch fashion.
Given a job and its resource request, a tuple of time/space, Miser
searches through a time/space pool, until it manages to find an
allocation that fits the job's requests. A successful allocation, called
the schedule, is a tuple consisting of a start and end time and the
resources allotted to the application during the interval defined. These
resources are guaranteed by the kernel during the schedule.
Miser manages the time/space pool using a hierarchy of resource vectors
indexed by time, using a system-wide quantum. All vectors are of equal
size. Each entry specifies a set of resources allocated to the vector: a
number of CPUs and an allocation of physical memory. The system vector
defines the set of resources allocated to Miser; all other vectors
allocate their resources from the system vector. Associated with each
vector is a vector definition (to allocate new entries as time advances),
a set of jobs scheduled against the resources of the vector, a policy
module that controls the scheduling of jobs, and miscellaneous policy-
related data. The collection of a resource vector and its associated
code and data structures is called a Queue.
The resource vector represents the time/space pool a Queue manages. The
length of the resource vector defines the length of the time dimension of
the time/space pool or the duration of the time/space pool, and is
defined to be the length of the system vector. The resource vector's
duration is not fixed in time, but rather represents how far into the
future the Queue can schedule resources. The actual amount of space
available at any point in time is defined by the vector definition. The
vector definition consists of a list of resource tuples. The resource
tuples contain a start and end time, and a quantity of space. The tuples
are ordered by their start and end times and these times are relative to
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midnight of UTC (see gettimeofday(3B)). The duration of the system
vector defines how far into the future relative to midnight of UTC the
last tuple's end time can be. The duration of the vector definition is
the time between time 0 and the end time of the last tuple. If the
duration is greater than the duration of the system vector, the vector
definition is truncated. If the vector definition is shorter, then it is
repeated. If the duration of the vector definition does not perfectly
divide into the system vector's duration, and is smaller, then the last
repetition of the vector definition is truncated.
Given that the origin for time is 00:00 Thursday Jan 1st, it is possible
to construct vector definitions for weeks, days or parts of days by
creating appropriate resource tuples. Note, time zero is time zero at
GMT adjusted for timezone difference, and daylight savings. For example,
a vector definition for a Queue that managed 10 CPUs and 1 gigabyte of
memory between 8:00pm and 4:00am and managed no resources between 4:00am
and 8:00pm would consist of two resource tuples, the first with a start
time of 00:00 hours and end time of 04:00 hours, and the second with a
start time of 20:00 hours and end time of 00:00 hours. The actual values
of the resource vector entries, depend on the value of the current time.
So if the current time was 4:00pm, then the entries corresponding to
4:00pm through 8:00pm would reflect that there was no available space;
the entries between 8:00pm and 4:00am would reflect that the resource
vector had 10 CPUs and 1g of memory to allocate; and between 4:00am and
4:00pm there were no resource available. In other words, the value of the
0 entry of the resource vector does not correspond to time 0 of the
vector definition. If the system vector was a week long, then the
resource vector definition would be repeated seven times. The Queue would
be able to schedule an application up to a week in advance of its
execution time.
The policy module defines the way in which a block of time/space is
searched to satisfy the resource request made by the application. The
two policies supplied with miser are the "default" and "repack" policy.
The "default policy is the first fit policy. In this policy once a job
is scheduled, its start and end time remains constant. The event of an
earlier job finishing ahead of schedule does not have any effect on the
start/end time of the future scheduled jobs. On the other hand the
"repack" policy does as its name implies. Each time any job ends on a
queue with a repack policy the entire job schedule is reevaluated and
updated. When machine resources are freed due an executing job's early
termination, the repack policy will attempt to reschedule queued jobs,
pulling them ahead in time. While repacking endeavors to maintain the
FIFO order of queued jobs, a higher priority is given to the optimal
utilization of machine resources. The actual start and end times of a
job in a queue with a repack policy can potentially be earlier than its
initially reported start and end times.
SEE ALSOmiser(1), miser_submit(1), miser(4), miser_jinfo(1), miser_qinfo(1),
miser_move(1), miser_reset(1).
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