nccl/src/graph/xml.h

/*************************************************************************
 * Copyright (c) 2019-2021, NVIDIA CORPORATION. All rights reserved.
 *
 * See LICENSE.txt for license information
 ************************************************************************/

#ifndef XML_H_
#define XML_H_

// A few constraints to make the implementation easy
#define MAX_STR_LEN 255
#define MAX_ATTR_COUNT 16
#define MAX_SUBS 32
#define MAX_NODES 1024

#define NODE_TYPE_NONE 0
#define NODE_TYPE_OPEN 1
#define NODE_TYPE_CLOSE 2
#define NODE_TYPE_SINGLE 3

struct ncclXmlNode {
  char name[MAX_STR_LEN+1];
  struct {
    char key[MAX_STR_LEN+1];
    char value[MAX_STR_LEN+1];
  } attrs[MAX_ATTR_COUNT+1]; // Need an extra one to consume extra params
  int nAttrs;
  int type;
  struct ncclXmlNode* parent;
  struct ncclXmlNode* subs[MAX_SUBS];
  int nSubs;
};

struct ncclXml {
  struct ncclXmlNode nodes[MAX_NODES];
  int maxIndex;
};

/* File functions */
#define NCCL_TOPO_XML_VERSION 1
ncclResult_t ncclTopoGetXmlFromFile(const char* xmlTopoFile, struct ncclXml* xml);
ncclResult_t ncclTopoDumpXmlToFile(const char* xmlTopoFile, struct ncclXml* xml);
#define NCCL_GRAPH_XML_VERSION 1
ncclResult_t ncclTopoGetXmlGraphFromFile(const char* xmlGraphFile, struct ncclXml* xml);

/* Auto-detect functions */
ncclResult_t ncclTopoFillGpu(struct ncclXml* xml, const char* busId, struct ncclXmlNode** gpuNode);
ncclResult_t ncclTopoFillNet(struct ncclXml* xml, const char* pciPath, const char* netName, struct ncclXmlNode** netNode);

/* Remove unneeded parts */
ncclResult_t ncclTopoTrimXml(struct ncclXml* xml);

/**************/
/* XML Struct */
/* Functions  */
/**************/

static ncclResult_t xmlGetAttrIndex(struct ncclXmlNode* node, const char* attrName, int* index) {
  *index = -1;
  const int nAttrs = node->nAttrs;
  for (int a=0; a<nAttrs; a++) {
    if (strncmp(node->attrs[a].key, attrName, MAX_STR_LEN) == 0) {
      *index = a;
      return ncclSuccess;
    }
  }
  return ncclSuccess;
}

static ncclResult_t xmlGetAttr(struct ncclXmlNode* node, const char* attrName, const char** value) {
  int index;
  NCCLCHECK(xmlGetAttrIndex(node, attrName, &index));
  *value = index == -1 ? NULL : node->attrs[index].value;
  return ncclSuccess;
}

static ncclResult_t xmlGetAttrStr(struct ncclXmlNode* node, const char* attrName, const char** value) {
  NCCLCHECK(xmlGetAttr(node, attrName, value));
  if (*value == NULL) {
    WARN("Attribute %s of node %s not found", attrName, node->name);
    return ncclInternalError;
  }
  return ncclSuccess;
}
static ncclResult_t xmlGetAttrInt(struct ncclXmlNode* node, const char* attrName, int* value) {
  const char* str;
  NCCLCHECK(xmlGetAttrStr(node, attrName, &str));
  *value = strtol(str, NULL, 0);
  return ncclSuccess;
}

static ncclResult_t xmlGetAttrFloat(struct ncclXmlNode* node, const char* attrName, float* value) {
  const char* str;
  NCCLCHECK(xmlGetAttrStr(node, attrName, &str));
  *value = strtof(str, NULL);
  return ncclSuccess;
}

static ncclResult_t xmlFindTag(struct ncclXml* xml, const char* tagName, struct ncclXmlNode** node) {
  *node = NULL;
  for (int i=0; i<xml->maxIndex; i++) {
    struct ncclXmlNode* n = xml->nodes+i;
    if (strcmp(n->name, tagName) == 0) {
      *node = n;
      return ncclSuccess;
    }
  }
  return ncclSuccess;
}

static ncclResult_t xmlFindTagKv(struct ncclXml* xml, const char* tagName, struct ncclXmlNode** node, const char* attrName, const char* attrValue) {
  *node = NULL;
  for (int i=0; i<xml->maxIndex; i++) {
    struct ncclXmlNode* n = xml->nodes+i;
    if (strcmp(n->name, tagName) == 0) {
      const char* value;
      NCCLCHECK(xmlGetAttr(n, attrName, &value));
      if (value && strcmp(value, attrValue) == 0) {
        *node = n;
        return ncclSuccess;
      }
    }
  }
  return ncclSuccess;
}

static ncclResult_t xmlSetAttr(struct ncclXmlNode* node, const char* attrName, const char* value) {
  int index;
  NCCLCHECK(xmlGetAttrIndex(node, attrName, &index));
  if (index == -1) {
    index = node->nAttrs++;
    strncpy(node->attrs[index].key, attrName, MAX_STR_LEN);
    node->attrs[index].key[MAX_STR_LEN] = '\0';
  }
  strncpy(node->attrs[index].value, value, MAX_STR_LEN);
  node->attrs[index].value[MAX_STR_LEN] = '\0';
  return ncclSuccess;
}

static ncclResult_t xmlSetAttrInt(struct ncclXmlNode* node, const char* attrName, const int value) {
  int index;
  NCCLCHECK(xmlGetAttrIndex(node, attrName, &index));
  if (index == -1) {
    index = node->nAttrs++;
    strncpy(node->attrs[index].key, attrName, MAX_STR_LEN);
    node->attrs[index].key[MAX_STR_LEN] = '\0';
  }
  snprintf(node->attrs[index].value, MAX_STR_LEN, "%d", value);
  node->attrs[index].value[MAX_STR_LEN] = '\0';
  return ncclSuccess;
}

static ncclResult_t xmlSetAttrFloat(struct ncclXmlNode* node, const char* attrName, const float value) {
  int index;
  NCCLCHECK(xmlGetAttrIndex(node, attrName, &index));
  if (index == -1) {
    index = node->nAttrs++;
    strncpy(node->attrs[index].key, attrName, MAX_STR_LEN);
    node->attrs[index].key[MAX_STR_LEN] = '\0';
  }
  snprintf(node->attrs[index].value, MAX_STR_LEN, "%g", value);
  node->attrs[index].value[MAX_STR_LEN] = '\0';
  return ncclSuccess;
}

static ncclResult_t xmlUnsetAttr(struct ncclXmlNode* node, const char* attrName) {
  int index;
  NCCLCHECK(xmlGetAttrIndex(node, attrName, &index));
  if (index == -1) return ncclSuccess;
  for (int i=index+1; i<node->nAttrs; i++) {
    strcpy(node->attrs[i-1].key, node->attrs[i].key);
    strcpy(node->attrs[i-1].value, node->attrs[i].value);
  }
  node->nAttrs--;
  return ncclSuccess;
}

static ncclResult_t xmlGetSub(struct ncclXmlNode* node, const char* subName, struct ncclXmlNode** sub) {
  *sub = NULL;
  for (int s=0; s<node->nSubs; s++) {
    if (strcmp(node->subs[s]->name, subName) == 0) {
      *sub = node->subs[s];
      return ncclSuccess;
    }
  }
  return ncclSuccess;
}

static ncclResult_t xmlGetSubKv(struct ncclXmlNode* node, const char* subName, struct ncclXmlNode** sub, const char* attrName, const char* attrValue) {
  *sub = NULL;
  for (int s=0; s<node->nSubs; s++) {
    struct ncclXmlNode* subNode = node->subs[s];
    if (strcmp(subNode->name, subName) == 0) {
      const char* value;
      NCCLCHECK(xmlGetAttr(subNode, attrName, &value));
      if (value && strcmp(value, attrValue) == 0) {
        *sub = node->subs[s];
        return ncclSuccess;
      }
    }
  }
  return ncclSuccess;
}
static ncclResult_t xmlGetSubKvInt(struct ncclXmlNode* node, const char* subName, struct ncclXmlNode** sub, const char* attrName, const int attrValue) {
  char strValue[10];
  snprintf(strValue, 10, "%d", attrValue);
  NCCLCHECK(xmlGetSubKv(node, subName, sub, attrName, strValue));
  return ncclSuccess;
}

static ncclResult_t xmlAddNode(struct ncclXml* xml, struct ncclXmlNode* parent, const char* subName, struct ncclXmlNode** sub) {
  if (xml->maxIndex == MAX_NODES) {
    WARN("Error : too many XML nodes (max %d)", MAX_NODES);
    return ncclInternalError;
  }
  struct ncclXmlNode* s = xml->nodes+xml->maxIndex++;
  s->nSubs = 0;
  s->nAttrs = 0;
  *sub = s;
  s->parent = parent;
  if (parent) parent->subs[parent->nSubs++] = s;
  strncpy(s->name, subName, MAX_STR_LEN);
  s->name[MAX_STR_LEN] = '\0';
  return ncclSuccess;
}

static ncclResult_t xmlRemoveNode(struct ncclXmlNode* node) {
  node->type = NODE_TYPE_NONE;
  struct ncclXmlNode* parent = node->parent;
  if (parent == NULL) return ncclSuccess;
  int shift = 0;
  for (int s=0; s<parent->nSubs; s++) {
    if (parent->subs[s] == node) shift = 1;
    else if (shift) parent->subs[s-1] = parent->subs[s];
  }
  parent->nSubs--;
  return ncclSuccess;
}

// Dictionary for STR -> INT conversions. No dictionary size information,
// there needs to be a last element with str == NULL.
struct kvDict {
  const char* str;
  int value;
};

static ncclResult_t kvConvertToInt(const char* str, int* value, struct kvDict* dict) {
  struct kvDict* d = dict;
  while (d->str) {
    if (strncmp(str, d->str, strlen(d->str)) == 0) {
      *value = d->value;
      return ncclSuccess;
    }
    d++;
  }
  INFO(NCCL_GRAPH, "KV Convert to int : could not find value of '%s' in dictionary, falling back to %d", str, d->value);
  *value = d->value;
  return ncclSuccess;
}
static ncclResult_t kvConvertToStr(int value, const char** str, struct kvDict* dict) {
  struct kvDict* d = dict;
  while (d->str) {
    if (value == d->value) {
      *str = d->str;
      return ncclSuccess;
    }
    d++;
  }
  WARN("KV Convert to str : could not find value %d in dictionary", value);
  return ncclInternalError;
}

#endif