Changes between Version 5 and Version 6 of HomogeneousRedundancy

Timestamp:

Jul 6, 2007, 11:37:43 AM (17 years ago)

Author:

davea

Comment:

--

HomogeneousRedundancy

@@ -11 +11 @@
 == Homogeneous redundancy ==
 
-BOINC provides a feature called '''homogeneous redundancy''' (HR) to handle divergent applications. You can enable it for a project by including the line
+BOINC provides a feature called '''homogeneous redundancy''' (HR) to handle divergent applications.
+HR divides hosts into 'numerical equivalence classes': two hosts are in the same class if they return identical results for your applications.
+The BOINC scheduler will send results for a given workunit only to hosts in the same class;
+this lets you use strict equality to compare redundant results.
+
+You can enable HR for a project by including the line
 {{{
 <homogeneous_redundancy>N</homogeneous_redundancy>
@@ -17 +22 @@
 in the [ProjectConfigFile config.xml] file, where N is the "HR type" to use (see below).
 
-Alternatively, you can enable it selectively for a single application by setting the `homogeneous_redundancy` field in its database record to the HR type for use with that application.
-
-Homogeneous redundancy divides hosts into 'numerical equivalence classes': two hosts are in the same class if they return identical results for your applications.
-The BOINC scheduler will send results for a given workunit only to hosts in the same class;
-this lets you use strict equality to compare redundant results.
+Alternatively, you can enable HR for a single application by setting the `homogeneous_redundancy` field in its database record to the HR type for use with that application.
 
 An "HR type" is a host classification.
@@ -37 +38 @@
 This allows them to use HR type 2.
 
-You can modify these HR types, or add your own, by editing the file
+There are two ways to find what HR type is needed for a given application.
+The bottom-up approach is to use a fine classification,
+and (by manually examining result files)
+identify classes that can be merged.
+The top-down approach is to use a coarse classification (e.g., 0)
+and (by analyzing the hosts involved in validation failures)
+identify host types that much go in separate classes.
+
+You can modify the pre-defined HR types, or add your own, by editing the file
 '''sched/hr.C'''.