COLL TUNED: remove stray selection of linear algs for alreduce and allgather

These selections seem harmful in my measurements and don't seem to be
motivated by previous measurement data.

Signed-off-by: Joseph Schuchart <schuchart@icl.utk.edu>

Author: devreal

ompi/mca/coll/tuned/coll_tuned_decision_fixed.c

@@ -92,30 +92,10 @@ ompi_coll_tuned_allreduce_intra_dec_fixed(const void *sbuf, void *rbuf, int coun
             } else {
                 alg = 2;
             }
-        } else if (communicator_size < 32) {
-            alg = 3;
-        } else if (communicator_size < 64) {
-            if (total_dsize < 131072) {
-                alg = 1;
-            } else {
-                alg = 3;
-            }
         } else if (communicator_size < 128) {
-            if (total_dsize < 128) {
-                alg = 1;
-            } else if (total_dsize < 512) {
-                alg = 3;
-            } else if (total_dsize < 8192) {
-                alg = 1;
-            } else {
-                alg = 3;
-            }
+            alg = 3;
         } else if (communicator_size < 256) {
-            if (total_dsize < 2048) {
-                alg = 2;
-            } else if (total_dsize < 16384) {
-                alg = 1;
-            } else if (total_dsize < 131072) {
+            if (total_dsize < 131072) {
                 alg = 2;
             } else if (total_dsize < 524288) {
                 alg = 3;
@@ -183,23 +163,13 @@ ompi_coll_tuned_allreduce_intra_dec_fixed(const void *sbuf, void *rbuf, int coun
                 alg = 6;
             }
         } else if (communicator_size < 128) {
-            if (total_dsize < 128) {
-                alg = 1;
-            } else if (total_dsize < 512) {
-                alg = 3;
-            } else if (total_dsize < 8192) {
-                alg = 1;
-            } else if (total_dsize < 262144) {
+            if (total_dsize < 262144) {
                 alg = 3;
             } else {
                 alg = 6;
             }
         } else if (communicator_size < 256) {
-            if (total_dsize < 2048) {
-                alg = 2;
-            } else if (total_dsize < 16384) {
-                alg = 1;
-            } else if (total_dsize < 131072) {
+            if (total_dsize < 131072) {
                 alg = 2;
             } else if (total_dsize < 262144) {
                 alg = 3;
@@ -1158,19 +1128,15 @@ int ompi_coll_tuned_allgather_intra_dec_fixed(const void *sbuf, int scount,
             alg = 4;
         }
     } else if (communicator_size < 128) {
-        if (total_dsize < 64) {
-            alg = 1;
-        } else if (total_dsize < 512) {
+        if (total_dsize < 512) {
             alg = 3;
         } else if (total_dsize < 65536) {
             alg = 5;
         } else {
             alg = 4;
         }
     } else if (communicator_size < 256) {
-        if (total_dsize < 32) {
-            alg = 1;
-        } else if (total_dsize < 512) {
+        if (total_dsize < 512) {
             alg = 3;
         } else if (total_dsize < 131072) {
             alg = 5;
@@ -1182,9 +1148,7 @@ int ompi_coll_tuned_allgather_intra_dec_fixed(const void *sbuf, int scount,
             alg = 4;
         }
     } else if (communicator_size < 512) {
-        if (total_dsize < 16) {
-            alg = 1;
-        } else if (total_dsize < 32) {
+        if (total_dsize < 32) {
             alg = 3;
         } else if (total_dsize < 128) {
             alg = 2;
@@ -1200,9 +1164,7 @@ int ompi_coll_tuned_allgather_intra_dec_fixed(const void *sbuf, int scount,
             alg = 4;
         }
     } else if (communicator_size < 1024) {
-        if (total_dsize < 4) {
-            alg = 1;
-        } else if (total_dsize < 64) {
+        if (total_dsize < 64) {
             alg = 3;
         } else if (total_dsize < 256) {
             alg = 2;
@@ -1212,9 +1174,7 @@ int ompi_coll_tuned_allgather_intra_dec_fixed(const void *sbuf, int scount,
             alg = 5;
         }
     } else if (communicator_size < 2048) {
-        if (total_dsize < 2) {
-            alg = 1;
-        } else if (total_dsize < 4) {
+        if (total_dsize < 4) {
             alg = 3;
         } else if (total_dsize < 8) {
             alg = 2;