Changes between Version 4 and Version 5 of CreditNew

Author:

davea (IP: 71.202.248.143)

Timestamp:

11/03/09 10:23:53 (3 weeks ago)

Comment:

--

CreditNew

@@ -199 +199 @@
-
-Notes:
+ * This mechanism reduces the claimed credit of hosts
+   that are less efficient than average,
+   and increases the claimed credit of hosts that are more efficient
+   than average.
- * VNPFC* is averaged over jobs, not hosts.
- * Both averages are exponential recent averages,
-   so that they respond to changes in job sizes and app versions characteristics.
- * This assumes that all hosts are sent the same distribution of jobs.
-   There are two situations where this is not the case:
-   a) job-size matching, and b) GPUGrid.net's scheme for sending
-   some (presumably larger) jobs to GPUs with more processors.
+   This can be dealt with using app units (see below).
+
+== Computing averages ==
+
+We need to compute averages carefully because
+
+ * The quantities being averaged may gradually change over time
+   (e.g. average job size may change,
+   app version efficiency may change as new versions are deployed)
+   and we need to track this.
+ * A given sample may be wildly off,
+   and we can't let this mess up the average.
+
+In addition, we may as well maintain the standard deviation
+of the quantities,
+although the current system doesn't use it.
+
+So for each quantity we maintain the following object:
+{{{
+struct STATS {
+    int nsamples;
+    double sum;
+    double exp_avg;
+
+    void update(double sample) {
+    }
+
+    double mean() {
+    }
+};
+}}}
+
+== Jobs versus app units ==
-   To deal with this, we can weight jobs by workunit.rsc_flops_est.
-
-
-
-
-
-
-
+
+
-
-== Cross-project scaling factors ==
-  subsequent jobs will be replicated.
-
+== Job runtime estimates ==
+
-== Implementation ==
-