FR2840705A1 - Load balancing method for a parallel-connected PC cluster used in processing a single digital video image, whereby objects in the image are divided into sub-objects in such a way that duplicated processing is minimized - Google Patents

Abstract

Load balancing method for a parallel-connected PC cluster, with each PC processing a zone or region (R1-Rn) of a digital image, has the following steps: dividing an initial image (I) into a number of regions and meshing of objects in the image using a number of geometric elementary shapes. Additionally for each image: each object is decomposed into a number of sub-objects (SOi, SOj, SOk) each obtained by grouping elementary shapes (Fi), the number of sub-object intersections with the object boundary are determined and the elementary shapes are rearrangement to minimize the number of intersections. An Independent claim is made for a device for balancing the load on a parallel cluster of PCs used in processing a digital image.

Description

op is the algorithmic operator.

  A method and device for load balancing within a cluster used in parallel for graphics applications The present invention relates to a method of load balancing within a cluster (cluster). ) computers used in parallel for graphical applications. Wile also aims at a device for the implementation

this process.

  There are already load balancing techniques within a parallel computer cluster used to process portions of an image in real time. Each computer is associated with a portion or region of the same image. Each image has one or more objects, each

  object that can be broken down into soul-objects.

  An existing balancing technique is based on border displacement between the different regions. But there is an effect of redundancy calculations made by several computers assigned to adjacent regions of the same image because a same soul-object is thus calculated several times, which causes a high calculation time that can warn in certain prohibitive configurations for use

real time graph.

  The object of the present invention is to solve this disadvantage by proposing a load balancing method which makes it possible to reduce the probability that a same object or soul-object is treated by several machines. This objective is achieved with a method for balancing the load of a set (cluster) of computers used in parallel and each assigned to the calculation of a zone or region of a digital image, comprising for each image, a preliminary decoupage of image in several regions each of which a computer is assigned, and a mesh of the object or objects present in the image according to a plurality of geometric shapes

3 o elementary.

  According to the invention, the method of load balancing further comprises, for each image: a decomposition to said object in a plurality of soul-objects each obtained by grouping elementary geometric shapes, a calculation of the imprint a cross-reference check comprising a determination of the number of intersections to said subject-object with region boundaries, and - an adjustment of the groupings of elementary geometrical forms of

  to minimize the number of intersections.

  Thus, with the load balancing method according to the invention, the likelihood of redundancy is significantly reduced since the wind loads are constructed so that they are included in only one region and therefore do not wind up.

  processed only by the machine assigned to that particular area.

  The elementary geometric shapes may include polyhedra. Other advantages and features of the invention will be apparent from

  the examination of the detailed description of a mode of implementation by no means

  and FIG. 1 schematically represents an image processed with the load balancing method according to the invention; and - Figure 2 schematically illustrates a computer cluster for which the

  load balancing method is implemented.

  We will now describe, with reference to the above figures, an example of setting the balance of the balancing process according to the invention in

  same time as the device allowing this implementation.

  A cluster C of computers M1,, Mi, Mn driven by a control unit U is connected to which connected devices and computer equipment, including a screen E. The pilot unit U is adapted to operate a graphics processing. digital image by assigning to each of the regions of the same image a computer of the cluster C. The unit U includes in particular a D device for balancing the computing load provided by each of the computers in the cluster. This device D is designed to cover the process

  load balancing system according to the invention.

  For each digital image 1, a preliminary cut is performed so as to provide a set of regions R1, .., Ri, .. Rn, for example in the form of rectangles of regular size. Each object O present in ['image I is decomposed into a set of elementary objects or object objects SO1,... SO \,..., SON obtained by aggregation or grouping of elementary geometric forms Fi,

  for example elementary triangles.

  The load balancing device D then calculates the fingerprint of each soul-object on the screen, defined here as a rectangle encompassing the projection of the soul-object on the screen, and determines the number of intersections.

  of this soul-object with the borders of the regions of the image.

  The groupings of the basic geometric shapes are adjusted to minimize the number of intersections for each of the soul-objects. We then obtain an optimized set of soul-objects completely included in a single region and thus each treated by a

only computer.

  Of course, the invention is not limited to the examples just described and many improvements can be made to these examples.

  examples without departing from the scope of the invention.

- 4 -

Claims (5)

  1. Method for balancing the load of a set (cluster) (C) of computers (M 1, .., Mi, .. Mn) used in parallel and each assigned to the calculation of a zone or region (R1, .., Ri, .. Rn) diune digital image (I), comprising for each image: - a preliminary decoupage of ['image (I) in several regions (R1, .., Ri, .., Rn) each of which a computer is assigned, - a mesh of the object or objects (O) present in ['image (I) according to a plurality of elementary geometrical shapes (F), characterized in that it further comprises, for each image: a decomposition to said object (O) into a plurality of soul-objects (SOi, SOj, SO k) each obtained by a group of elementary geometric shapes (F), - a calculation of the fingerprint of each soul-object comprising a determination of the number of intersections auditing the soul-object with the boundaries of regions, and - an adjustment of the groupings of geometric forms   in order to minimize the number of intersections.   2. Method according to claim 1, characterized in that the forms   Basic geometrics include polyhedra.   3. Method according to one of claims 1 or 2, characterized in that   regions of rectangular shape.   4. Device (D) for balancing the load of a set (C) (cluster) of computers (M 1, .., Mi, .., Mn) used in parallel and each assigned to the calculation of a zone or region (Ri) of a digital image (I), comprising: - means for realizing for each image a preliminary cutting of said image into several regions 3 each of which a computer is affected, - means for making a mesh of the object or objects present in the image according to a plurality of elementary geometric shapes, characterized in that it further comprises: means for performing a decomposition to said object in a plurality of soul-objects each obtained by grouping geometric shapes elementary means for calculating the footprint of each soul-object comprising a determination of the number of intersections to said soul-object with the region borders, and means for adjusting the groupings of elementary geometric shapes so as to minimize the number of inter sections. 5. Application of the load balancing method according to one of the   1 to 3, for a computer cluster adapted to the treatment