nccl/src/misc/utils.cc

/*************************************************************************
 * Copyright (c) 2016-2020, NVIDIA CORPORATION. All rights reserved.
 *
 * See LICENSE.txt for license information
 ************************************************************************/

#include "utils.h"
#include "core.h"

#include "nvmlwrap.h"

// Get current Compute Capability
int ncclCudaCompCap() {
  int cudaDev;
  if (cudaGetDevice(&cudaDev) != cudaSuccess) return 0;
  int ccMajor, ccMinor;
  if (cudaDeviceGetAttribute(&ccMajor, cudaDevAttrComputeCapabilityMajor, cudaDev) != cudaSuccess) return 0;
  if (cudaDeviceGetAttribute(&ccMinor, cudaDevAttrComputeCapabilityMinor, cudaDev) != cudaSuccess) return 0;
  return ccMajor*10+ccMinor;
}

ncclResult_t int64ToBusId(int64_t id, char* busId) {
  sprintf(busId, "%04lx:%02lx:%02lx.%01lx", (id) >> 20, (id & 0xff000) >> 12, (id & 0xff0) >> 4, (id & 0xf));
  return ncclSuccess;
}

ncclResult_t busIdToInt64(const char* busId, int64_t* id) {
  const int size = strlen(busId);
  char* hexStr;
  NCCLCHECK(ncclCalloc(&hexStr, size));
  int hexOffset = 0;
  for (int i=0; i<size; i++) {
    char c = busId[i];
    if (c == '.' || c == ':') continue;
    if ((c >= '0' && c <= '9') ||
        (c >= 'A' && c <= 'F') ||
        (c >= 'a' && c <= 'f')) {
      hexStr[hexOffset++] = busId[i];
    } else break;
  }
  hexStr[hexOffset] = '\0';
  *id = strtol(hexStr, NULL, 16);
  free(hexStr);
  return ncclSuccess;
}

// Convert a logical cudaDev index to the NVML device minor number
ncclResult_t getBusId(int cudaDev, int64_t *busId) {
  // On most systems, the PCI bus ID comes back as in the 0000:00:00.0
  // format. Still need to allocate proper space in case PCI domain goes
  // higher.
  char busIdStr[] = "00000000:00:00.0";
  CUDACHECK(cudaDeviceGetPCIBusId(busIdStr, sizeof(busIdStr), cudaDev));
  NCCLCHECK(busIdToInt64(busIdStr, busId));
  return ncclSuccess;
}

ncclResult_t getHostName(char* hostname, int maxlen, const char delim) {
  if (gethostname(hostname, maxlen) != 0) {
    strncpy(hostname, "unknown", maxlen);
    return ncclSystemError;
  }
  int i = 0;
  while ((hostname[i] != delim) && (hostname[i] != '\0') && (i < maxlen-1)) i++;
  hostname[i] = '\0';
  return ncclSuccess;
}

uint64_t getHash(const char* string, int n) {
  // Based on DJB2a, result = result * 33 ^ char
  uint64_t result = 5381;
  for (int c = 0; c < n; c++) {
    result = ((result << 5) + result) ^ string[c];
  }
  return result;
}

/* Generate a hash of the unique identifying string for this host
 * that will be unique for both bare-metal and container instances
 * Equivalent of a hash of;
 *
 * $(hostname)$(cat /proc/sys/kernel/random/boot_id)
 *
 * This string can be overridden by using the NCCL_HOSTID env var.
 */
#define HOSTID_FILE "/proc/sys/kernel/random/boot_id"
uint64_t getHostHash(void) {
  char hostHash[1024];
  char *hostId;

  // Fall back is the full hostname if something fails
  (void) getHostName(hostHash, sizeof(hostHash), '\0');
  int offset = strlen(hostHash);

  if ((hostId = getenv("NCCL_HOSTID")) != NULL) {
    INFO(NCCL_ENV, "NCCL_HOSTID set by environment to %s", hostId);
    strncpy(hostHash, hostId, sizeof(hostHash));
  } else {
    FILE *file = fopen(HOSTID_FILE, "r");
    if (file != NULL) {
      char *p;
      if (fscanf(file, "%ms", &p) == 1) {
        strncpy(hostHash+offset, p, sizeof(hostHash)-offset-1);
        free(p);
      }
    }
    fclose(file);
  }

  // Make sure the string is terminated
  hostHash[sizeof(hostHash)-1]='\0';

  TRACE(NCCL_INIT,"unique hostname '%s'", hostHash);

  return getHash(hostHash, strlen(hostHash));
}

/* Generate a hash of the unique identifying string for this process
 * that will be unique for both bare-metal and container instances
 * Equivalent of a hash of;
 *
 * $$ $(readlink /proc/self/ns/pid)
 */
uint64_t getPidHash(void) {
  char pname[1024];
  // Start off with our pid ($$)
  sprintf(pname, "%ld", (long) getpid());
  int plen = strlen(pname);
  int len = readlink("/proc/self/ns/pid", pname+plen, sizeof(pname)-1-plen);
  if (len < 0) len = 0;

  pname[plen+len]='\0';
  TRACE(NCCL_INIT,"unique PID '%s'", pname);

  return getHash(pname, strlen(pname));
}

int parseStringList(const char* string, struct netIf* ifList, int maxList) {
  if (!string) return 0;

  const char* ptr = string;

  int ifNum = 0;
  int ifC = 0;
  char c;
  do {
    c = *ptr;
    if (c == ':') {
      if (ifC > 0) {
        ifList[ifNum].prefix[ifC] = '\0';
        ifList[ifNum].port = atoi(ptr+1);
        ifNum++; ifC = 0;
      }
      while (c != ',' && c != '\0') c = *(++ptr);
    } else if (c == ',' || c == '\0') {
      if (ifC > 0) {
        ifList[ifNum].prefix[ifC] = '\0';
        ifList[ifNum].port = -1;
        ifNum++; ifC = 0;
      }
    } else {
      ifList[ifNum].prefix[ifC] = c;
      ifC++;
    }
    ptr++;
  } while (ifNum < maxList && c);
  return ifNum;
}

static bool matchIf(const char* string, const char* ref, bool matchExact) {
  // Make sure to include '\0' in the exact case
  int matchLen = matchExact ? strlen(string) + 1 : strlen(ref);
  return strncmp(string, ref, matchLen) == 0;
}

static bool matchPort(const int port1, const int port2) {
  if (port1 == -1) return true;
  if (port2 == -1) return true;
  if (port1 == port2) return true;
  return false;
}


bool matchIfList(const char* string, int port, struct netIf* ifList, int listSize, bool matchExact) {
  // Make an exception for the case where no user list is defined
  if (listSize == 0) return true;

  for (int i=0; i<listSize; i++) {
    if (matchIf(string, ifList[i].prefix, matchExact)
        && matchPort(port, ifList[i].port)) {
      return true;
    }
  }
  return false;
}