TABLE OF CONTENTS

librkl/cpu_properties [ package ]

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Synopsis

  set of X86 utilities for cpu type and properties determination

EXAMPLES

Fortran example:

program test_feature
  use ISO_C_BINDING
  implicit none
#define IN_FORTRAN_CODE
#include <cpu_properties.h>
  real(C_DOUBLE) :: s1, s2
  integer(C_INT64_T) :: t1, t2
  integer :: status
  if(cpu_has_feature(FLAG_AVX2) .ne. 0) print *,'AVX2'
  if(cpu_has_feature(FLAG_AVX) .ne. 0) print *,'AVX'
  if(cpu_has_feature(FLAG_FMA) .ne. 0) print *,'FMA'
  if(cpu_has_feature(FLAG_BMI) .ne. 0) print *,'BMI'
  if(cpu_has_feature(FLAG_SSE4) .ne. 0) print *,'SSE4'
  if(cpu_has_feature(FLAG_SSE3) .ne. 0) print *,'SSE3'
  if(cpu_has_feature(FLAG_SSE2) .ne. 0) print *,'SSE2'
  status = get_fp_status_ctl()
  print 100,' FP status = ',status
100 format(A,Z8)
  if(iand(FP_STATUS_PE,status) .ne. 0) print *,"Precision ON"
  if(iand(FP_STATUS_UE,status) .ne. 0) print *,"Underflow ON"
  if(iand(FP_STATUS_OE,status) .ne. 0) print *,"Overflow ON"
  if(iand(FP_STATUS_ZE,status) .ne. 0) print *,"Zero divide ON"
  print *,'CPU number =',get_cpu_number()
  stop
end

result of Fortran program execution on i3-6100 CPU @ 3.70GHz :

 AVX2
 AVX
 FMA
 BMI
 SSE4
 SSE3
 SSE2
 FP status =     1FA0
 Precision ON

C example:

#include <stdint.h>
#include <stdio.h>
#include <cpu_properties.h>
int main(int argc, char** argv)
{
 uint64_t t1, t2;
 double s1, s2;
 int status;
 printf("CPU speed: %lu Hz\n",get_cpu_freq());
 printf("FLAGS: ");
 if(cpu_has_feature(FLAG_SSE))  printf(" SSE");
 if(cpu_has_feature(FLAG_SSE2)) printf(" SSE2");
 if(cpu_has_feature(FLAG_SSE3)) printf(" SSE3");
 if(cpu_has_feature(FLAG_SSE4)) printf(" SSE4");
 if(cpu_has_feature(FLAG_AVX))  printf(" AVX");
 if(cpu_has_feature(FLAG_FMA))  printf(" FMA");
 if(cpu_has_feature(FLAG_AVX2)) printf(" AVX2");
 printf("\n");
 status = get_fp_status_ctl();
 printf("FPU status = %8.8x\n",status);
 printf("Precision status %s\n",status & FP_STATUS_PE ? "ON" : "OFF");
 printf("Underflow status %s\n",status & FP_STATUS_UE ? "ON" : "OFF");
 printf("Overflow status %s\n",status & FP_STATUS_OE ? "ON" : "OFF");
 printf("Zero divide status %s\n",status & FP_STATUS_ZE ? "ON" : "OFF");
 return(0);
}

result of C program execution on i3-6100 CPU @ 3.70GHz :

CPU speed: 3700000000 Hz
FLAGS:  SSE SSE2 SSE3 SSE4 AVX FMA AVX2
FPU status = 00001fa0
Precision status ON
Underflow status OFF
Overflow status OFF
Zero divide status OFF

librkl/cpu_has_feature [ Functions ]

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FUNCTION

   determine whether certain capabilities are present on the current CPU
   e.g. AVX/AVX2/SSE2/FMA ...

Synopsis

  C:
   int cpu_has_feature(int feature);

  Fortran:
   interface
     function cpu_has_feature(feature) result(status)
       import C_INT
       integer(C_INT), intent(IN), value :: feature
       integer(C_INT) :: status
     end function cpu_has_feature
   end interface

  #include <cpu_type.h> 
  is usable by C and Fortran programs alike

  Fortran programs MUST use
  #define IN_FORTRAN_CODE
  before including cpu_type.h

ARGUMENTS

    feature : feature symbol from cpu_type (#include <cpu_type.h>)

RESULT

  1 is feature is supported by CPU, 0 otherwise

AUTHOR

  M.Valin Recherche en Prevision Numerique 2016

librkl/get_cpu_cores [ Functions ]

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FUNCTION

   get the number of cores of this CPU

Synopsis

 C:
   int get_cpu_cores();

 Fortran:
   interface
     function get_cpu_cores() result(ncores)
       import C_INT
       integer(C_INT) :: ncores
     end function get_cpu_cores
   end interface

ARGUMENTS

    none

RESULT

  the number of cores of this CPU (not one on X86 family cpus only)

AUTHOR

  M.Valin Recherche en Prevision Numerique 2016

librkl/get_cpu_freq [ Functions ]

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FUNCTION

  get the CPU nominal frequency

Synopsis

  C:
   uint64_t get_cpu_freq();

  Fortran:
   interface
     function get_cpu_freq() result(freq)
       import C_INT64_T
       integer(C_INT64_T) :: freq
     end function get_cpu_freq
   end interface

ARGUMENTS

    none

RESULT

  the CPU nominal frequency in Hertz (64 bit unsigned integer) 
  (nonzero on X86 family cpus only)

AUTHOR

  M.Valin Recherche en Prevision Numerique 2016

librkl/get_cpu_hyperthreads [ Functions ]

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FUNCTION

   get the number of hyperthreads of this CPU

Synopsis

 C:
   int get_cpu_hyperthreads();

 Fortran:
   interface
     function get_cpu_hyperthreads() result(nhyperthreads)
       import C_INT
       integer(C_INT) :: nhyperthreads
     end function get_cpu_hyperthreads
   end interface

ARGUMENTS

    none

RESULT

  the number of hyperthreads of this CPU (not 1 on X86 family cpus only)

AUTHOR

  M.Valin Recherche en Prevision Numerique 2016

librkl/get_cpu_number [ Functions ]

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FUNCTION

   get the processor number of this CPU in the node

Synopsis

 C:
   int get_cpu_number();

 Fortran:
   interface
     function get_cpu_number() result(id)
       import C_INT
       integer(C_INT) :: id
     end function get_cpu_number
   end interface

ARGUMENTS

    none

RESULT

  the APIC id of the current cpu (nozero on X86 family cpus only)
 
  to be correlated with /proc/cpuinfo to find actual CPU number

AUTHOR

  M.Valin Recherche en Prevision Numerique 2016

librkl/get_fp_status_ctl [ Functions ]

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FUNCTION

   get floating point status word

Synopsis

 C:
   int get_fp_status_ctl();

 Fortran:
   interface
     function get_fp_status_ctl() result(id)
       import C_INT
       integer(C_INT) :: id
     end function get_fp_status_ctl
   end interface

ARGUMENTS

    none

RESULT

  the floating point status word (nozero on X86 family cpus only)

AUTHOR

  M.Valin Recherche en Prevision Numerique 2016

librkl/set_fp_status_ctl [ Functions ]

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FUNCTION

   set the floating point status and control word

Synopsis

 C:
   void set_fp_status_ctl(int id);

 Fortran:
   interface
     subroutine set_fp_status_ctl(id)
       import C_INT
       integer(C_INT), intent(IN), value :: id
     end subroutine set_fp_status_ctl
   end interface

ARGUMENTS

    id : integer value to store into the floating point status and control word
         (X86 family cpus only)

AUTHOR

  M.Valin Recherche en Prevision Numerique 2016