added timing-analysis.txt

git-svn-id: svn://anubis/gvsu@183 45c1a28c-8058-47b2-ae61-ca45b979098e

cs677/pa2/timing-analysis.txt

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+Times for big.seq and big.unk on mp:
+
+Sequential: 5.33091 sec
+Threaded:
+  num_threads   time
+  1             10.7522
+  2             11.1476
+  4             15.0832
+  8             36.2662
+
+The threaded version is slower in general than the sequential version because
+there is a lot more logic involved in each step for calculating the indices
+into the matrix and traversing it along diagonals instead of row-wise.
+With more threads, the threaded version also has to synchronize more (each of
+the threads does a barrier wait at the end of each step). Since some threads
+do not have much work, especially at the beginning and end of the algorithm,
+this leads to more time being taken doing the synchronization than the actual
+computation.
+
+In contrast, when the "unknown" search sequence grows in length and the known
+database sequence shrinks, such that the two sequences are "more even" in
+length, then the threaded version does much better because there is less
+synchronization required compared to the amount of actual computation being
+done:
+
+Times for more-even.seq and more-even.unk on mp:
+
+Sequential: 1.34995 sec
+Threaded:
+  num_threads   time
+  1             10.0506
+  2             4.26101
+  4             2.7733
+  8             2.64885