linux-common.c

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/*
* File:    linux-common.c
*/
 
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <err.h>
#include <stdarg.h>
#include <stdio.h>
#include <errno.h>
#include <syscall.h>
#include <sys/utsname.h>
#include <sys/time.h>
 
#include "papi.h"
#include "papi_internal.h"
#include "papi_vector.h"
 
#include "linux-memory.h"
#include "linux-common.h"
#include "linux-timer.h"
 
#include "x86_cpuid_info.h"
 
PAPI_os_info_t _papi_os_info;
 
/* The locks used by Linux */
 
#if defined(USE_PTHREAD_MUTEXES)
pthread_mutex_t _papi_hwd_lock_data[PAPI_MAX_LOCK];
#elif defined(USE_LIBAO_ATOMICS)
AO_TS_t _papi_hwd_lock_data[PAPI_MAX_LOCK];
#else
volatile unsigned int _papi_hwd_lock_data[PAPI_MAX_LOCK];
#endif
 
 
static int _linux_init_locks(void) {
 
   int i;
 
   for ( i = 0; i < PAPI_MAX_LOCK; i++ ) {
#if defined(USE_PTHREAD_MUTEXES)
       pthread_mutex_init(&_papi_hwd_lock_data[i],NULL);
#elif defined(USE_LIBAO_ATOMICS)
       _papi_hwd_lock_data[i] = AO_TS_INITIALIZER;
#else
       _papi_hwd_lock_data[i] = MUTEX_OPEN;
#endif
   }
 
   return PAPI_OK;
}
 
 
int
_linux_detect_hypervisor(char *virtual_vendor_name) {
 
    int retval=0;
 
#if defined(__i386__)||defined(__x86_64__)
    retval=_x86_detect_hypervisor(virtual_vendor_name);
#else
    (void) virtual_vendor_name;
#endif
 
    return retval;
}
 
 
#define _PATH_SYS_SYSTEM "/sys/devices/system"
#define _PATH_SYS_CPU0   _PATH_SYS_SYSTEM "/cpu/cpu0"
 
static char pathbuf[PATH_MAX] = "/";
 
static char *
search_cpu_info( FILE * f, char *search_str)
{
    static char line[PAPI_HUGE_STR_LEN] = "";
    char *s, *start = NULL;
 
    rewind(f);
 
    while (fgets(line,PAPI_HUGE_STR_LEN,f)!=NULL) {
        s=strstr(line,search_str);
        if (s!=NULL) {
            /* skip all characters in line up to the colon */
            /* and then spaces */
            s=strchr(s,':');
            if (s==NULL) break;
            s++;
            while (isspace(*s)) {
                s++;
            }
            start = s;
            /* Find and clear newline */
            s=strrchr(start,'\n');
            if (s!=NULL) *s = 0;
            break;
        }
    }
    return start;
}
 
static void
decode_vendor_string( char *s, int *vendor )
{
    if ( strcasecmp( s, "GenuineIntel" ) == 0 )
        *vendor = PAPI_VENDOR_INTEL;
    else if ( ( strcasecmp( s, "AMD" ) == 0 ) ||
              ( strcasecmp( s, "AuthenticAMD" ) == 0 ) )
        *vendor = PAPI_VENDOR_AMD;
    else if ( strcasecmp( s, "IBM" ) == 0 )
        *vendor = PAPI_VENDOR_IBM;
    else if ( strcasecmp( s, "Cray" ) == 0 )
        *vendor = PAPI_VENDOR_CRAY;
    else if ( strcasecmp( s, "ARM_ARM" ) == 0 )
        *vendor = PAPI_VENDOR_ARM_ARM;
    else if ( strcasecmp( s, "ARM_BROADCOM" ) == 0 )
        *vendor = PAPI_VENDOR_ARM_BROADCOM;
    else if ( strcasecmp( s, "ARM_CAVIUM" ) == 0 )
        *vendor = PAPI_VENDOR_ARM_CAVIUM;
    else if ( strcasecmp( s, "ARM_FUJITSU" ) == 0 )
        *vendor = PAPI_VENDOR_ARM_FUJITSU;
    else if ( strcasecmp( s, "ARM_HISILICON") == 0 )
        *vendor = PAPI_VENDOR_ARM_HISILICON;
    else if ( strcasecmp( s, "ARM_APM" ) == 0 )
        *vendor = PAPI_VENDOR_ARM_APM;
    else if ( strcasecmp( s, "ARM_QUALCOMM" ) == 0 )
        *vendor = PAPI_VENDOR_ARM_QUALCOMM;
    else if ( strcasecmp( s, "MIPS" ) == 0 )
        *vendor = PAPI_VENDOR_MIPS;
    else if ( strcasecmp( s, "SiCortex" ) == 0 )
        *vendor = PAPI_VENDOR_MIPS;
    else
        *vendor = PAPI_VENDOR_UNKNOWN;
}
 
static FILE *
xfopen( const char *path, const char *mode )
{
    FILE *fd = fopen( path, mode );
    if ( !fd )
        err( EXIT_FAILURE, "error: %s", path );
    return fd;
}
 
static FILE *
path_vfopen( const char *mode, const char *path, va_list ap )
{
    vsnprintf( pathbuf, sizeof ( pathbuf ), path, ap );
    return xfopen( pathbuf, mode );
}
 
 
static int
path_sibling( const char *path, ... )
{
    int c;
    long n;
    int result = 0;
    char s[2];
    FILE *fp;
    va_list ap;
    va_start( ap, path );
    fp = path_vfopen( "r", path, ap );
    va_end( ap );
 
    while ( ( c = fgetc( fp ) ) != EOF ) {
        if ( isxdigit( c ) ) {
            s[0] = ( char ) c;
            s[1] = '\0';
            for ( n = strtol( s, NULL, 16 ); n > 0; n /= 2 ) {
                if ( n % 2 )
                    result++;
            }
        }
    }
 
    fclose( fp );
    return result;
}
 
static int
path_exist( const char *path, ... )
{
    va_list ap;
    va_start( ap, path );
    vsnprintf( pathbuf, sizeof ( pathbuf ), path, ap );
    va_end( ap );
    return access( pathbuf, F_OK ) == 0;
}
 
static int
decode_cpuinfo_x86( FILE *f, PAPI_hw_info_t *hwinfo )
{
    int tmp;
    unsigned int strSize;
    char *s;
 
    /* Stepping */
    s = search_cpu_info( f, "stepping");
    if ( s ) {
        if (sscanf( s, "%d", &tmp ) ==1 ) {
            hwinfo->revision = ( float ) tmp;
            hwinfo->cpuid_stepping = tmp;
        }
    }
 
    /* Model Name */
    s = search_cpu_info( f, "model name");
    strSize = sizeof(hwinfo->model_string);
    if ( s ) {
        strncpy( hwinfo->model_string, s, strSize - 1);
    }
 
    /* Family */
    s = search_cpu_info( f, "cpu family");
    if ( s ) {
        sscanf( s, "%d", &tmp );
        hwinfo->cpuid_family = tmp;
    }
 
 
    /* CPU Model */
    s = search_cpu_info( f, "model");
    if ( s ) {
        sscanf( s , "%d", &tmp );
        hwinfo->model = tmp;
        hwinfo->cpuid_model = tmp;
    }
 
    return PAPI_OK;
}
 
static int
decode_cpuinfo_power(FILE *f, PAPI_hw_info_t *hwinfo )
{
 
    int tmp;
    unsigned int strSize;
    char *s;
 
    /* Revision */
    s = search_cpu_info( f, "revision");
    if ( s ) {
        sscanf( s, "%d", &tmp );
        hwinfo->revision = ( float ) tmp;
        hwinfo->cpuid_stepping = tmp;
    }
 
       /* Model Name */
    s = search_cpu_info( f, "model");
    strSize = sizeof(hwinfo->model_string);
    if ( s ) {
        strncpy( hwinfo->model_string, s, strSize - 1);
    }
 
    return PAPI_OK;
}
 
 
 
static int
decode_cpuinfo_arm(FILE *f, PAPI_hw_info_t *hwinfo )
{
 
    int tmp;
    unsigned int strSize;
    char *s, *t;
 
    /* revision */
    s = search_cpu_info( f, "CPU revision");
    if ( s ) {
        sscanf( s, "%d", &tmp );
        hwinfo->revision = ( float ) tmp;
        /* For compatability with old PAPI */
        hwinfo->model = tmp;
    }
 
    /* Model Name */
    s = search_cpu_info( f, "model name");
    strSize = sizeof(hwinfo->model_string);
    if ( s ) {
        strncpy( hwinfo->model_string, s, strSize - 1);
    }
 
    /* Architecture (ARMv6, ARMv7, ARMv8, etc.) */
 
    /* Parsing this is a bit fragile. */
    /* On ARM64 the "CPU architecture field" */
    /*     Prior to Linux 3.19: always "AArch64" */
    /*     Since Linux 3.19: always "8" */
    /* On ARM32 the "CPU architecture field" is a value and not */
    /*  necessarily an integer, so it might be 7 or 7M */
    /*  also, unknown architectures are assigned a value */
    /*  such as (10) where 10 does not mean version 10, just */
    /*  the 10th element in an array */
    /* Note the original Raspberry Pi lies in the CPU architecture line */
    /* (it's ARMv6 not ARMv7)                                  */
    /* So we should actually get the value from the            */
    /*  Processor/ model name line                         */
 
 
    s = search_cpu_info( f, "CPU architecture");
    if ( s ) {
 
        /* Handle old (prior to Linux 3.19) ARM64 */
        if (strstr(s,"AArch64")) {
            hwinfo->cpuid_family = 8;
        }
        else {
            hwinfo->cpuid_family=strtol(s, NULL, 10);
        }
 
        /* Old Fallbacks if the above didn't work */
        if (hwinfo->cpuid_family<0) {
 
            /* Try the processor field and look inside of parens */
            s = search_cpu_info( f, "Processor" );
            if (s) {
                t=strchr(s,'(');
                tmp=*(t+2)-'0';
                hwinfo->cpuid_family = tmp;
            }
            /* Try the model name and look inside of parens */
            else {
                s = search_cpu_info( f, "model name" );
                if (s) {
                    t=strchr(s,'(');
                    tmp=*(t+2)-'0';
                    hwinfo->cpuid_family = tmp;
                }
            }
        }
    }
 
    /* CPU Model */
    s = search_cpu_info( f, "CPU part" );
    if ( s ) {
        sscanf( s, "%x", &tmp );
        hwinfo->cpuid_model = tmp;
    }
 
    /* CPU Variant */
    s = search_cpu_info( f, "CPU variant" );
    if ( s ) {
        sscanf( s, "%x", &tmp );
        hwinfo->cpuid_stepping = tmp;
    }
 
    return PAPI_OK;
 
}
 
 
int
_linux_get_cpu_info( PAPI_hw_info_t *hwinfo, int *cpuinfo_mhz )
{
    int retval = PAPI_OK;
    char *s;
    float mhz = 0.0;
    FILE *f;
    char cpuinfo_filename[]="/proc/cpuinfo";
 
    if ( ( f = fopen( cpuinfo_filename, "r" ) ) == NULL ) {
        PAPIERROR( "fopen(/proc/cpuinfo) errno %d", errno );
        return PAPI_ESYS;
    }
 
    /* All of this information may be overwritten by the component */
 
    /***********************/
    /* Attempt to find MHz */
    /***********************/
    s = search_cpu_info( f, "cpu MHz" );
    if ( !s ) {
        s = search_cpu_info( f, "clock" );
    }
    if ( s ) {
        sscanf( s, "%f", &mhz );
        *cpuinfo_mhz = mhz;
    }
    else {
      *cpuinfo_mhz = -1;   // Could not find it.
    //  PAPIWARN("Failed to find a clock speed in /proc/cpuinfo");
    }
 
    /*******************************/
    /* Vendor Name and Vendor Code */
    /*******************************/
 
    /* First try to read "vendor_id" field */
    /* Which is the most common field      */
    s = search_cpu_info( f, "vendor_id");
    if ( s ) {
        strncpy( hwinfo->vendor_string, s, PAPI_MAX_STR_LEN );
      hwinfo->vendor_string[PAPI_MAX_STR_LEN-1]=0;
    }
    else {
        /* If not found, try "vendor" which seems to be Itanium specific */
        s = search_cpu_info( f, "vendor" );
        if ( s ) {
           strncpy( hwinfo->vendor_string, s, PAPI_MAX_STR_LEN );
         hwinfo->vendor_string[PAPI_MAX_STR_LEN-1]=0;
        }
        else {
            /* "system type" seems to be MIPS and Alpha */
            s = search_cpu_info( f, "system type");
            if ( s ) {
              strncpy( hwinfo->vendor_string, s, PAPI_MAX_STR_LEN );
            hwinfo->vendor_string[PAPI_MAX_STR_LEN-1]=0;
            }
            else {
                /* "platform" indicates Power */
                s = search_cpu_info( f, "platform");
                if ( s ) {
                    if ( ( strcasecmp( s, "pSeries" ) == 0 ) ||
                        ( strcasecmp( s, "PowerNV" ) == 0 ) ||
                        ( strcasecmp( s, "PowerMac" ) == 0 ) ) {
                        strcpy( hwinfo->vendor_string, "IBM" );
                    }
                }
                else {
                    /* "CPU implementer" indicates ARM */
                    /* For ARM processors, hwinfo->vendor >= PAPI_VENDOR_ARM_ARM(0x41). */
                    /* If implementer is ARM Limited., hwinfo->vendor == PAPI_VENDOR_ARM_ARM. */
                    /* If implementer is Cavium Inc., hwinfo->vendor == PAPI_VENDOR_ARM_CAVIUM(0x43). */
                    s = search_cpu_info( f, "CPU implementer");
                    if ( s ) {
                        int tmp;
                        sscanf( s, "%x", &tmp );
                        switch( tmp ) {
                        case PAPI_VENDOR_ARM_ARM:
                            strcpy( hwinfo->vendor_string, "ARM_ARM" );
                            break;
                        case PAPI_VENDOR_ARM_BROADCOM:
                            strcpy( hwinfo->vendor_string, "ARM_BROADCOM" );
                            break;
                        case PAPI_VENDOR_ARM_CAVIUM:
                            strcpy( hwinfo->vendor_string, "ARM_CAVIUM" );
                            break;
                        case PAPI_VENDOR_ARM_FUJITSU:
                            strcpy( hwinfo->vendor_string, "ARM_FUJITSU" );
                            break;
                        case PAPI_VENDOR_ARM_HISILICON:
                            strcpy( hwinfo->vendor_string, "ARM_HISILICON" );
                            break;
                        case PAPI_VENDOR_ARM_APM:
                            strcpy( hwinfo->vendor_string, "ARM_APM" );
                            break;
                        case PAPI_VENDOR_ARM_QUALCOMM:
                            strcpy( hwinfo->vendor_string, "ARM_QUALCOMM" );
                            break;
                        default:
                            strcpy( hwinfo->vendor_string, "ARM_UNKNOWN" );
                        }
                    }
                }
            }
        }
    }
 
    /* Decode the string to a PAPI specific implementer value */
    if ( strlen( hwinfo->vendor_string ) ) {
        decode_vendor_string( hwinfo->vendor_string, &hwinfo->vendor );
    }
 
    /**********************************************/
    /* Provide more stepping/model/family numbers */
    /**********************************************/
 
    if ((hwinfo->vendor==PAPI_VENDOR_INTEL) ||
        (hwinfo->vendor==PAPI_VENDOR_AMD)) {
 
        decode_cpuinfo_x86(f,hwinfo);
    }
 
    if (hwinfo->vendor==PAPI_VENDOR_IBM) {
 
        decode_cpuinfo_power(f,hwinfo);
    }
 
    if (hwinfo->vendor>=PAPI_VENDOR_ARM_ARM) {
 
        decode_cpuinfo_arm(f,hwinfo);
    }
 
 
 
 
    /* The following members are set using the same methodology */
    /* used in lscpu.                                           */
 
    /* Total number of CPUs */
    /* The following line assumes totalcpus was initialized to zero! */
    while ( path_exist( _PATH_SYS_SYSTEM "/cpu/cpu%d", hwinfo->totalcpus ) )
        hwinfo->totalcpus++;
 
    /* Number of threads per core */
    if ( path_exist( _PATH_SYS_CPU0 "/topology/thread_siblings" ) )
        hwinfo->threads =
            path_sibling( _PATH_SYS_CPU0 "/topology/thread_siblings" );
 
    /* Number of cores per socket */
    if ( path_exist( _PATH_SYS_CPU0 "/topology/core_siblings" ) &&
         hwinfo->threads > 0 )
        hwinfo->cores =
            path_sibling( _PATH_SYS_CPU0 "/topology/core_siblings" ) /
            hwinfo->threads;
 
    /* Number of NUMA nodes */
    /* The following line assumes nnodes was initialized to zero! */
    while ( path_exist( _PATH_SYS_SYSTEM "/node/node%d", hwinfo->nnodes ) ) {
        hwinfo->nnodes++;
    }
 
    /* Number of CPUs per node */
    hwinfo->ncpu = hwinfo->nnodes > 1 ?
            hwinfo->totalcpus / hwinfo->nnodes : hwinfo->totalcpus;
 
    /* Number of sockets */
    if ( hwinfo->threads > 0 && hwinfo->cores > 0 ) {
        hwinfo->sockets = hwinfo->totalcpus / hwinfo->cores / hwinfo->threads;
    }
 
#if 0
    int *nodecpu;
    /* cpumap data is not currently part of the _papi_hw_info struct */
        nodecpu = malloc( (unsigned int) hwinfo->nnodes * sizeof(int) );
    if ( nodecpu ) {
       int i;
       for ( i = 0; i < hwinfo->nnodes; ++i ) {
           nodecpu[i] = path_sibling(
                             _PATH_SYS_SYSTEM "/node/node%d/cpumap", i );
       }
    } else {
        PAPIERROR( "malloc failed for variable not currently used" );
    }
#endif
 
 
    /* Fixup missing Megahertz Value */
    /* This is missing from cpuinfo on ARM and MIPS */
    if (*cpuinfo_mhz < 1.0) {
        s = search_cpu_info( f, "BogoMIPS" );
        if ((!s) || (sscanf( s, "%f", &mhz ) != 1)) {
            INTDBG("MHz detection failed. "
                "Please edit file %s at line %d.\n",
                __FILE__,__LINE__);
        }
 
        if (hwinfo->vendor == PAPI_VENDOR_MIPS) {
            /* MIPS has 2x clock multiplier */
            *cpuinfo_mhz = 2*(((int)mhz)+1);
 
            /* Also update version info on MIPS */
            s = search_cpu_info( f, "cpu model");
            s = strstr(s," V")+2;
            strtok(s," ");
            sscanf(s, "%f ", &hwinfo->revision );
        }
        else {
            /* In general bogomips is proportional to number of CPUs */
            if (hwinfo->totalcpus) {
                if (mhz!=0) *cpuinfo_mhz = mhz / hwinfo->totalcpus;
            }
        }
    }
 
    fclose( f );
 
    return retval;
}
 
int
_linux_get_mhz( int *sys_min_mhz, int *sys_max_mhz ) {
 
  FILE *fff;
  int result;
 
  /* Try checking for min MHz */
  /* Assume cpu0 exists */
  fff=fopen("/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq","r");
  if (fff==NULL) return PAPI_EINVAL;
  result=fscanf(fff,"%d",sys_min_mhz);
  fclose(fff);
  if (result!=1) return PAPI_EINVAL;
 
  fff=fopen("/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq","r");
  if (fff==NULL) return PAPI_EINVAL;
  result=fscanf(fff,"%d",sys_max_mhz);
  fclose(fff);
  if (result!=1) return PAPI_EINVAL;
 
  return PAPI_OK;
 
}
 
int
_linux_get_system_info( papi_mdi_t *mdi ) {
 
    int retval;
    char maxargs[PAPI_HUGE_STR_LEN];
    pid_t pid;
    int cpuinfo_mhz,sys_min_khz,sys_max_khz;
 
    /* Software info */
 
    /* Path and args */
 
    pid = getpid(  );
    if ( pid < 0 ) {
        PAPIERROR( "getpid() returned < 0" );
        return PAPI_ESYS;
    }
    mdi->pid = pid;
 
    sprintf( maxargs, "/proc/%d/exe", ( int ) pid );
    retval = readlink( maxargs, mdi->exe_info.fullname,
            PAPI_HUGE_STR_LEN-1 );
    if ( retval < 0 ) {
        PAPIERROR( "readlink(%s) returned < 0", maxargs );
        return PAPI_ESYS;
    }
 
    if (retval > PAPI_HUGE_STR_LEN-1) {
        retval=PAPI_HUGE_STR_LEN-1;
    }
    mdi->exe_info.fullname[retval] = '\0';
 
    /* Careful, basename can modify its argument */
    strcpy( maxargs, mdi->exe_info.fullname );
 
    strncpy( mdi->exe_info.address_info.name, basename( maxargs ),
        PAPI_HUGE_STR_LEN-1);
    mdi->exe_info.address_info.name[PAPI_HUGE_STR_LEN-1] = '\0';
 
    SUBDBG( "Executable is %s\n", mdi->exe_info.address_info.name );
    SUBDBG( "Full Executable is %s\n", mdi->exe_info.fullname );
 
    /* Executable regions, may require reading /proc/pid/maps file */
 
    retval = _linux_update_shlib_info( mdi );
    SUBDBG( "Text: Start %p, End %p, length %d\n",
            mdi->exe_info.address_info.text_start,
            mdi->exe_info.address_info.text_end,
            ( int ) ( mdi->exe_info.address_info.text_end -
                      mdi->exe_info.address_info.text_start ) );
    SUBDBG( "Data: Start %p, End %p, length %d\n",
            mdi->exe_info.address_info.data_start,
            mdi->exe_info.address_info.data_end,
            ( int ) ( mdi->exe_info.address_info.data_end -
                      mdi->exe_info.address_info.data_start ) );
    SUBDBG( "Bss: Start %p, End %p, length %d\n",
            mdi->exe_info.address_info.bss_start,
            mdi->exe_info.address_info.bss_end,
            ( int ) ( mdi->exe_info.address_info.bss_end -
                      mdi->exe_info.address_info.bss_start ) );
 
    /* PAPI_preload_option information */
 
    strcpy( mdi->preload_info.lib_preload_env, "LD_PRELOAD" );
    mdi->preload_info.lib_preload_sep = ' ';
    strcpy( mdi->preload_info.lib_dir_env, "LD_LIBRARY_PATH" );
    mdi->preload_info.lib_dir_sep = ':';
 
    /* Hardware info */
 
    retval = _linux_get_cpu_info( &mdi->hw_info, &cpuinfo_mhz );
    if ( retval )
        return retval;
 
    /* Handle MHz */
 
    retval = _linux_get_mhz( &sys_min_khz, &sys_max_khz );
    if ( retval ) {
 
        mdi->hw_info.cpu_max_mhz=cpuinfo_mhz;
        mdi->hw_info.cpu_min_mhz=cpuinfo_mhz;
 
       /*
       mdi->hw_info.mhz=cpuinfo_mhz;
       mdi->hw_info.clock_mhz=cpuinfo_mhz;
       */
    }
    else {
        mdi->hw_info.cpu_max_mhz=sys_max_khz/1000;
        mdi->hw_info.cpu_min_mhz=sys_min_khz/1000;
 
       /*
       mdi->hw_info.mhz=sys_max_khz/1000;
       mdi->hw_info.clock_mhz=sys_max_khz/1000;
       */
    }
 
    /* Set Up Memory */
 
    retval = _linux_get_memory_info( &mdi->hw_info, mdi->hw_info.model );
    if ( retval )
        return retval;
 
    SUBDBG( "Found %d %s(%d) %s(%d) CPUs at %d Mhz.\n",
            mdi->hw_info.totalcpus,
            mdi->hw_info.vendor_string,
            mdi->hw_info.vendor,
                mdi->hw_info.model_string,
                mdi->hw_info.model,
                mdi->hw_info.cpu_max_mhz);
 
    /* Get virtualization info */
    mdi->hw_info.virtualized=_linux_detect_hypervisor(mdi->hw_info.virtual_vendor_string);
 
    return PAPI_OK;
}
 
int
_papi_hwi_init_os(void) {
 
    int major=0,minor=0,sub=0;
    char *ptr;
    struct utsname uname_buffer;
 
    /* Initialize the locks */
    _linux_init_locks();
 
    /* Get the kernel info */
    uname(&uname_buffer);
 
    SUBDBG("Native kernel version %s\n",uname_buffer.release);
 
    strncpy(_papi_os_info.name,uname_buffer.sysname,PAPI_MAX_STR_LEN);
 
#ifdef ASSUME_KERNEL
    strncpy(_papi_os_info.version,ASSUME_KERNEL,PAPI_MAX_STR_LEN);
    SUBDBG("Assuming kernel version %s\n",_papi_os_info.name);
#else
    strncpy(_papi_os_info.version,uname_buffer.release,PAPI_MAX_STR_LEN);
#endif
 
    ptr=strtok(_papi_os_info.version,".");
    if (ptr!=NULL) major=atoi(ptr);
 
    ptr=strtok(NULL,".");
    if (ptr!=NULL) minor=atoi(ptr);
 
    ptr=strtok(NULL,".");
    if (ptr!=NULL) sub=atoi(ptr);
 
   _papi_os_info.os_version=LINUX_VERSION(major,minor,sub);
 
   _papi_os_info.itimer_sig = PAPI_INT_MPX_SIGNAL;
   _papi_os_info.itimer_num = PAPI_INT_ITIMER;
   _papi_os_info.itimer_ns = PAPI_INT_MPX_DEF_US * 1000;
   _papi_os_info.itimer_res_ns = 1;
   _papi_os_info.clock_ticks = sysconf( _SC_CLK_TCK );
 
   /* Get Linux-specific system info */
   _linux_get_system_info( &_papi_hwi_system_info );
 
   return PAPI_OK;
}
 
 
 
int _linux_detect_nmi_watchdog() {
 
  int watchdog_detected=0,watchdog_value=0;
  FILE *fff;
 
  fff=fopen("/proc/sys/kernel/nmi_watchdog","r");
  if (fff!=NULL) {
     if (fscanf(fff,"%d",&watchdog_value)==1) {
        if (watchdog_value>0) watchdog_detected=1;
     }
     fclose(fff);
  }
 
  return watchdog_detected;
}
 
papi_os_vector_t _papi_os_vector = {
  .get_memory_info =   _linux_get_memory_info,
  .get_dmem_info =     _linux_get_dmem_info,
  .get_real_cycles =   _linux_get_real_cycles,
  .update_shlib_info = _linux_update_shlib_info,
  .get_system_info =   _linux_get_system_info,
 
 
#if defined(HAVE_CLOCK_GETTIME)
  .get_real_usec =  _linux_get_real_usec_gettime,
#elif defined(HAVE_GETTIMEOFDAY)
  .get_real_usec =  _linux_get_real_usec_gettimeofday,
#else
  .get_real_usec =  _linux_get_real_usec_cycles,
#endif
 
 
#if defined(USE_PROC_PTTIMER)
  .get_virt_usec =   _linux_get_virt_usec_pttimer,
#elif defined(HAVE_CLOCK_GETTIME_THREAD)
  .get_virt_usec =   _linux_get_virt_usec_gettime,
#elif defined(HAVE_PER_THREAD_TIMES)
  .get_virt_usec =   _linux_get_virt_usec_times,
#elif defined(HAVE_PER_THREAD_GETRUSAGE)
  .get_virt_usec =   _linux_get_virt_usec_rusage,
#endif
 
 
#if defined(HAVE_CLOCK_GETTIME)
  .get_real_nsec =  _linux_get_real_nsec_gettime,
#endif
 
#if defined(HAVE_CLOCK_GETTIME_THREAD)
  .get_virt_nsec =   _linux_get_virt_nsec_gettime,
#endif
 
 
};