coll tuned dynamic rules file alltoall_algorithm_max_requests

Teach the dynamic rules file reader to look for the
alltoall_algorithm_max_requests tuning parameter.  To keep the dynamic rules
file format backward compatible the alltoall_algorithm_max_requests is
optional. When not present in the rule definition the value of the
corresponding MCA variable is used instead.

Resolves #12589

Signed-off-by: Burlen Loring <bloring@nvidia.com>

Author: Burlen Loring

ompi/mca/coll/base/coll_base_util.c

@@ -12,6 +12,9 @@
  * Copyright (c) 2014-2020 Research Organization for Information Science
  *                         and Technology (RIST).  All rights reserved.
  * Copyright (c) 2023      Jeffrey M. Squyres.  All rights reserved.
+ *
+ * Copyright (c) 2024      NVIDIA CORPORATION. All rights reserved.
+ *
  * $COPYRIGHT$
  *
  * Additional copyrights may follow
@@ -482,6 +485,26 @@ int ompi_coll_base_file_peek_next_char_is(FILE *fptr, int *fileline, int expecte
     } while (1);
 }
 
+/**
+ * return non-zero if the next non-space to read on the current line is a digit.
+ * otherwise return 0.
+ */
+int ompi_coll_base_file_peek_next_char_isdigit(FILE *fptr)
+{
+    do {
+        int next = fgetc(fptr);
+
+        if ((' ' == next) || ('\t' == next)) {
+            continue; /* discard space and tab. keep everything else */
+        }
+
+        ungetc(next, fptr); /* put the char back into the stream */
+
+        return isdigit(next); /* report back whether or not next is a digit */
+
+    } while (1);
+}
+
 /**
  * There are certainly simpler implementation for this function when performance
  * is not a critical point. But, as this function is used during the collective

ompi/mca/coll/base/coll_base_util.h

@@ -11,6 +11,7 @@
  *                         All rights reserved.
  * Copyright (c) 2014-2020 Research Organization for Information Science
  *                         and Technology (RIST).  All rights reserved.
+ * Copyright (c) 2024      NVIDIA CORPORATION. All rights reserved.
  * $COPYRIGHT$
  *
  * Additional copyrights may follow
@@ -195,6 +196,7 @@ int ompi_coll_base_file_getnext_string(FILE *fptr, int *fileline, char** val);
  * eat the value, otherwise put it back into the file.
  */
 int ompi_coll_base_file_peek_next_char_is(FILE *fptr, int *fileline, int expected);
+int ompi_coll_base_file_peek_next_char_isdigit(FILE *fptr);
 
 /* Miscellaneous function */
 const char* mca_coll_base_colltype_to_str(int collid);

ompi/mca/coll/tuned/coll_tuned_dynamic_file.c

@@ -12,6 +12,7 @@
  * Copyright (c) 2015      Research Organization for Information Science
  *                         and Technology (RIST). All rights reserved.
  * Copyright (c) 2023      Jeffrey M. Squyres.  All rights reserved.
+ * Copyright (c) 2024      NVIDIA CORPORATION. All rights reserved.
  * $COPYRIGHT$
  *
  * Additional copyrights may follow
@@ -42,13 +43,24 @@
 static int fileline=0; /* used for verbose error messages */
 
 #define getnext(fptr, pval)        ompi_coll_base_file_getnext_long(fptr, &fileline, pval)
+#define isnext_digit(fptr)         ompi_coll_base_file_peek_next_char_isdigit(fptr)
 
 /*
  * Reads a rule file called fname
- * Builds the algorithm rule table for a max of n_collectives
+ * The rule file defines a set of sets of rules. The outer set is keyed on
+ * communicator size while the inner set is keyed on message size.  When a
+ * communicator is constructed its size is used to look up the nested set of
+ * message size keyed rules.  When a collective is called the message size
+ * determined from its call arguments are used to lookup a specific rule in the
+ * inner set.
+ *
+ * Rules for communicator and message sizes 0 and N (where N is the larger than
+ * largest key you provide) can be specified to fall back to the fixed decision
+ * framework above and below the communicator and message size ranges of
+ * interest.
  *
  * If an error occurs it removes rule table and then exits with a very verbose
- * error message (this stops the user using a half baked rule table
+ * error message. this stops the user using a half baked rule table.
  *
  * Returns the number of actual collectives that a rule exists for
  * (note 0 is NOT an error)
@@ -57,7 +69,16 @@ static int fileline=0; /* used for verbose error messages */
 
 int ompi_coll_tuned_read_rules_config_file (char *fname, ompi_coll_alg_rule_t** rules, int n_collectives)
 {
-    long CI, NCS, CS, ALG, NMS, FANINOUT, X, MS, SS;
+    long NCOL = 0,      /* number of collectives for which rules are provided  */
+         COLID = 0,     /* identifies the collective type to associate the rules with */
+         NCOMSIZES = 0, /* number of sets of message size rules. the key is communicator size */
+         COMSIZE = 0,   /* communicator size, the key identifying a specific set of message size rules. */
+         NMSGSIZES = 0, /* number of message size rules in the set. */
+         MSGSIZE = 0,   /* message size, the key identifying a specific rule in the set. */
+         ALG = 0,       /* the collective specific algorithm to use */
+         FANINOUT = 0,  /* algorithm specific tuning parameter */
+         SEGSIZE = 0,   /* algorithm specific tuning parameter */
+         MAXREQ = 0;    /* algorithm specific tuning parameter */
     FILE *fptr = (FILE*) NULL;
     int x, ncs, nms;
 
@@ -103,106 +124,126 @@ int ompi_coll_tuned_read_rules_config_file (char *fname, ompi_coll_alg_rule_t**
         goto on_file_error;
     }
 
-    if( (getnext(fptr, &X) < 0) || (X < 0) ) {
+    /* get the number of collectives for which rules are provided in the file */
+    if( (getnext(fptr, &NCOL) < 0) || (NCOL < 0) ) {
         OPAL_OUTPUT((ompi_coll_tuned_stream,"Could not read number of collectives in configuration file around line %d\n", fileline));
         goto on_file_error;
     }
-    if (X>n_collectives) {
-        OPAL_OUTPUT((ompi_coll_tuned_stream,"Number of collectives in configuration file %ld is greater than number of MPI collectives possible %d ??? error around line %d\n", X, n_collectives, fileline));
+    if (NCOL>n_collectives) {
+        OPAL_OUTPUT((ompi_coll_tuned_stream,"Number of collectives in configuration file %ld is greater than number of MPI collectives possible %d ??? error around line %d\n", NCOL, n_collectives, fileline));
         goto on_file_error;
     }
 
-    for (x=0;x<X;x++) { /* for each collective */
+    for (x=0;x<NCOL;x++) { /* for each collective */
 
-        if( (getnext(fptr, &CI) < 0) || (CI < 0) ) {
+        /* get the collective for which rules are being provided */
+        if( (getnext(fptr, &COLID) < 0) || (COLID < 0) ) {
             OPAL_OUTPUT((ompi_coll_tuned_stream,"Could not read next Collective id in configuration file around line %d\n", fileline));
             goto on_file_error;
         }
-        if (CI>=n_collectives) {
-            OPAL_OUTPUT((ompi_coll_tuned_stream,"Collective id in configuration file %ld is greater than MPI collectives possible %d. Error around line %d\n", CI, n_collectives, fileline));
+        if (COLID>=n_collectives) {
+            OPAL_OUTPUT((ompi_coll_tuned_stream,"Collective id in configuration file %ld is greater than MPI collectives possible %d. Error around line %d\n", COLID, n_collectives, fileline));
             goto on_file_error;
         }
 
-        if (alg_rules[CI].alg_rule_id != CI) {
-            OPAL_OUTPUT((ompi_coll_tuned_stream, "Internal error in handling collective ID %ld\n", CI));
+        if (alg_rules[COLID].alg_rule_id != COLID) {
+            OPAL_OUTPUT((ompi_coll_tuned_stream, "Internal error in handling collective ID %ld\n", COLID));
             goto on_file_error;
         }
-        OPAL_OUTPUT((ompi_coll_tuned_stream, "Reading dynamic rule for collective ID %ld\n", CI));
-        alg_p = &alg_rules[CI];
+        OPAL_OUTPUT((ompi_coll_tuned_stream, "Reading dynamic rule for collective ID %ld\n", COLID));
+        alg_p = &alg_rules[COLID];
 
-        alg_p->alg_rule_id = CI;
+        alg_p->alg_rule_id = COLID;
         alg_p->n_com_sizes = 0;
         alg_p->com_rules = (ompi_coll_com_rule_t *) NULL;
 
-        if( (getnext (fptr, &NCS) < 0) || (NCS < 0) ) {
-            OPAL_OUTPUT((ompi_coll_tuned_stream,"Could not read count of communicators for collective ID %ld at around line %d\n", CI, fileline));
+        /* get the number of communicator sizes for which a set of rules are to be provided */
+        if( (getnext (fptr, &NCOMSIZES) < 0) || (NCOMSIZES < 0) ) {
+            OPAL_OUTPUT((ompi_coll_tuned_stream,"Could not read count of communicators for collective ID %ld at around line %d\n", COLID, fileline));
             goto on_file_error;
         }
-        OPAL_OUTPUT((ompi_coll_tuned_stream, "Read communicator count %ld for dynamic rule for collective ID %ld\n", NCS, CI));
-        alg_p->n_com_sizes = NCS;
-        alg_p->com_rules = ompi_coll_tuned_mk_com_rules (NCS, CI);
+        OPAL_OUTPUT((ompi_coll_tuned_stream, "Read communicator count %ld for dynamic rule for collective ID %ld\n", NCOMSIZES, COLID));
+        alg_p->n_com_sizes = NCOMSIZES;
+        alg_p->com_rules = ompi_coll_tuned_mk_com_rules (NCOMSIZES, COLID);
         if (NULL == alg_p->com_rules) {
             OPAL_OUTPUT((ompi_coll_tuned_stream,"Cannot allocate com rules for file [%s]\n", fname));
             goto on_file_error;
         }
 
-        for (ncs=0;ncs<NCS;ncs++) {	/* for each comm size */
+        for (ncs=0;ncs<NCOMSIZES;ncs++) {	/* for each comm size */
 
             com_p = &(alg_p->com_rules[ncs]);
 
-            if( (getnext (fptr, &CS) < 0) || (CS < 0) ) {
-                OPAL_OUTPUT((ompi_coll_tuned_stream,"Could not read communicator size for collective ID %ld com rule %d at around line %d\n", CI, ncs, fileline));
+            /* get the communicator size to associate the set of rules with */
+            if( (getnext (fptr, &COMSIZE) < 0) || (COMSIZE < 0) ) {
+                OPAL_OUTPUT((ompi_coll_tuned_stream,"Could not read communicator size for collective ID %ld com rule %d at around line %d\n", COLID, ncs, fileline));
                 goto on_file_error;
             }
 
-            com_p->mpi_comsize = CS;
+            com_p->mpi_comsize = COMSIZE;
 
-            if( (getnext (fptr, &NMS) < 0) || (NMS < 0) ) {
-                OPAL_OUTPUT((ompi_coll_tuned_stream,"Could not read number of message sizes for collective ID %ld com rule %d at around line %d\n", CI, ncs, fileline));
+            /* get the number of message sizes to specify rules for. inner set size */
+            if( (getnext (fptr, &NMSGSIZES) < 0) || (NMSGSIZES < 0) ) {
+                OPAL_OUTPUT((ompi_coll_tuned_stream,"Could not read number of message sizes for collective ID %ld com rule %d at around line %d\n", COLID, ncs, fileline));
                 goto on_file_error;
             }
             OPAL_OUTPUT((ompi_coll_tuned_stream, "Read message count %ld for dynamic rule for collective ID %ld and comm size %ld\n",
-                         NMS, CI, CS));
-            com_p->n_msg_sizes = NMS;
-            com_p->msg_rules = ompi_coll_tuned_mk_msg_rules (NMS, CI, ncs, CS);
+                         NMSGSIZES, COLID, COMSIZE));
+            com_p->n_msg_sizes = NMSGSIZES;
+            com_p->msg_rules = ompi_coll_tuned_mk_msg_rules (NMSGSIZES, COLID, ncs, COMSIZE);
             if (NULL == com_p->msg_rules) {
                 OPAL_OUTPUT((ompi_coll_tuned_stream,"Cannot allocate msg rules for file [%s]\n", fname));
                 goto on_file_error;
             }
 
             msg_p = com_p->msg_rules;
 
-            for (nms=0;nms<NMS;nms++) {	/* for each msg size */
+            for (nms=0;nms<NMSGSIZES;nms++) {	/* for each msg size */
 
                 msg_p = &(com_p->msg_rules[nms]);
 
-                if( (getnext (fptr, &MS) < 0) || (MS < 0) ) {
-                    OPAL_OUTPUT((ompi_coll_tuned_stream,"Could not read message size for collective ID %ld com rule %d msg rule %d at around line %d\n", CI, ncs, nms, fileline));
+                /* read the message size to associate the rule with */
+                if( (getnext (fptr, &MSGSIZE) < 0) || (MSGSIZE < 0) ) {
+                    OPAL_OUTPUT((ompi_coll_tuned_stream,"Could not read message size for collective ID %ld com rule %d msg rule %d at around line %d\n", COLID, ncs, nms, fileline));
                     goto on_file_error;
                 }
-                msg_p->msg_size = (size_t)MS;
+                msg_p->msg_size = (size_t)MSGSIZE;
 
+                /* read the collective specific algorithm identifier */
                 if( (getnext (fptr, &ALG) < 0) || (ALG < 0) ) {
-                    OPAL_OUTPUT((ompi_coll_tuned_stream,"Could not read target algorithm method for collective ID %ld com rule %d msg rule %d at around line %d\n", CI, ncs, nms, fileline));
+                    OPAL_OUTPUT((ompi_coll_tuned_stream,"Could not read target algorithm method for collective ID %ld com rule %d msg rule %d at around line %d\n", COLID, ncs, nms, fileline));
                     goto on_file_error;
                 }
                 msg_p->result_alg = ALG;
 
+                /* read faninout tuning parameter. required */
                 if( (getnext (fptr, &FANINOUT) < 0) || (FANINOUT < 0) ) {
-                    OPAL_OUTPUT((ompi_coll_tuned_stream,"Could not read fan in/out topo for collective ID %ld com rule %d msg rule %d at around line %d\n", CI, ncs, nms, fileline));
+                    OPAL_OUTPUT((ompi_coll_tuned_stream,"Could not read fan in/out topo for collective ID %ld com rule %d msg rule %d at around line %d\n", COLID, ncs, nms, fileline));
                     goto on_file_error;
                 }
                 msg_p->result_topo_faninout = FANINOUT;
 
-                if( (getnext (fptr, &SS) < 0) || (SS < 0) ) {
-                    OPAL_OUTPUT((ompi_coll_tuned_stream,"Could not read target segment size for collective ID %ld com rule %d msg rule %d at around line %d\n", CI, ncs, nms, fileline));
+                /* read segsize tuning parameter. required */
+                if( (getnext (fptr, &SEGSIZE) < 0) || (SEGSIZE < 0) ) {
+                    OPAL_OUTPUT((ompi_coll_tuned_stream,"Could not read target segment size for collective ID %ld com rule %d msg rule %d at around line %d\n", COLID, ncs, nms, fileline));
                     goto on_file_error;
                 }
-                msg_p->result_segsize = SS;
+                msg_p->result_segsize = SEGSIZE;
+
+                /* read the max requests tuning parameter. optional */
+                msg_p->result_max_requests = ompi_coll_tuned_alltoall_max_requests;
+                if( isnext_digit(fptr) ) {
+                    if( (getnext (fptr, &MAXREQ) < 0) || (MAXREQ < 0) ) {
+                        OPAL_OUTPUT((ompi_coll_tuned_stream,"Could not read max requests for collective ID %ld com rule %d msg rule %d at around line %d\n", COLID, ncs, nms, fileline));
+                        goto on_file_error;
+                    }
+                    msg_p->result_max_requests = MAXREQ;
+                }
 
-                if (!nms && MS) {
+                /* check the first rule is for 0 size. look-up depends on this */
+                if (!nms && MSGSIZE) {
                     OPAL_OUTPUT((ompi_coll_tuned_stream,"All algorithms must specify a rule for message size of zero upwards always first!\n"));
-                    OPAL_OUTPUT((ompi_coll_tuned_stream,"Message size was %lu for collective ID %ld com rule %d msg rule %d at around line %d\n", MS, CI, ncs, nms, fileline));
+                    OPAL_OUTPUT((ompi_coll_tuned_stream,"Message size was %lu for collective ID %ld com rule %d msg rule %d at around line %d\n", MSGSIZE, COLID, ncs, nms, fileline));
                     goto on_file_error;
                 }
 
@@ -219,7 +260,7 @@ int ompi_coll_tuned_read_rules_config_file (char *fname, ompi_coll_alg_rule_t**
         } /* comm size */
 
         total_alg_count++;
-        OPAL_OUTPUT((ompi_coll_tuned_stream, "Done reading dynamic rule for collective ID %ld\n", CI));
+        OPAL_OUTPUT((ompi_coll_tuned_stream, "Done reading dynamic rule for collective ID %ld\n", COLID));
 
     } /* per collective */