Clean up output and fix optimization problem

Author: rweed

timers/Makefile

@@ -4,8 +4,8 @@ SHELL=/bin/sh
 .SUFFIXES: .o .F90 .f90
 
 FC=ifx
-FCFLAGS=-O2 -march=native -D__linux__
-FXFLAGS=-O2 -march=native -D__linux__
+FCFLAGS=-O2 -march=native
+FXFLAGS=-O2 -march=native
 
 # For Linux OS add -D__linux__ to FCFLAGS and FXFLAGS
 

timers/README.txt

@@ -16,16 +16,11 @@
   Each function is used to time a summation over 1.E8 iterations. Two
   get the Linux specific timers you must add -D__linux__ to your compiler
   options. test_timers.F90 also tests the Fortran intrinsic CPU_TIME which
-  is called directly. 
+  is called directly.
 
-  The test program defaults to compiling with -O0 optimization to give some
-  realisitic time values. Compiling with higher optimization can lead to 
-  some of the results returning 0 to 15 decimals places. This is thought to be
-  due to SYSTEM_CLOCK and DATE_AND_TIME having a finite interval between when
-  the results returned by these routines are updated. For -02 optimization, the
-  time taken in the summation loops is probably less than the update interval
-  for these routines resulting in the same value for the starting and ending
-  times used in the test program
+  You can change the number of iterations by adding -D__IMAX__=x and
+  -D__JMAX=y where x and y are integer values to the compile options
+  for test_timers.F90 
 
   These programs were compiled and tested on a Linux Mint 21.3 system running on  an AMD Ryzen 5 5600x processor with the following compilers
 
@@ -46,4 +41,3 @@
 
    flang     4.2
 
-

timers/test_timers.F90

@@ -3,20 +3,28 @@ Program test_timers
   USE ISO_FORTRAN_ENV, WP=>REAL64 
   USE timers
 
-#define __JMAX__ 10000
-#define __IMAX__ 10000
+#ifndef __JMAX__
+  #define __JMAX__ 10000
+#endif
+#ifndef __IMAX__
+ #define __IMAX__ 10000
+#endif
 
   Implicit NONE
 
+  Integer  :: niters
   Real(WP) :: time_s, time_e, sum, delta
 
+  Character(22) :: buf
+
   Integer :: i, j
 
+  niters = (__IMAX__)*(__JMAX__)
   Print *,'' 
   Print *,' *** Test of Fortran and C timer routines ***'
-  Print *,'' 
-  Print *,' C gettimeofday'
-  Print *,'' 
+  Print *,''
+  Write (*, '(" Summation loops elapsed times for ",i0," iterations")') niters 
+  Print *,''
   sum    = 0.0_WP
   time_e = 0.0_WP
   time_s = 0.0_WP
@@ -28,11 +36,9 @@ Program test_timers
   End Do 
   Call timer_gtd(time_e)
   delta = time_e - time_s
-  Write(*,'( " delta time C ctd                 = ", g0.15)') delta 
+  Write(*,'( " C gettimeofday                   = ", 1PE22.15)') delta 
+  Write(buf,'(1PE22.15)') sum
 
-  Print *,'' 
-  Print *,' C clock_gettime with MONOTONIC clock'
-  Print *,'' 
   sum    = 0.0_WP
   time_e = 0.0_WP
   time_s = 0.0_WP
@@ -44,11 +50,9 @@ Program test_timers
   End Do 
   Call timer_cgt(time_e, CLOCK_MONOTONIC)
   delta = time_e - time_s
-  Write(*,'( " delta time C cgt monotonic       = ", g0.15)') delta 
+  Write(*,'( " C clock_gettime (MONOTONIC)      = ", 1PE22.15)') delta 
+  Write(buf,'(1PE22.15)') sum
 
-  Print *,'' 
-  Print *,' C clock_gettime with REALTIME clock'
-  Print *,'' 
   sum    = 0.0_WP
   time_e = 0.0_WP
   time_s = 0.0_WP
@@ -60,11 +64,10 @@ Program test_timers
   End Do 
   Call timer_cgt(time_e, CLOCK_REALTIME)
   delta = time_e - time_s
-  Write(*,'( " delta time C cgt realtime        = ", g0.15)') delta 
+  Write(*,'( " C clock_gettime (REALTIME)       = ", 1PE22.15)') delta 
+  Write(buf,'(1PE22.15)') sum
+
 #ifdef __linux__ 
-  Print *,'' 
-  Print *,' C clock_gettime with CLOCK_THREAD_CPUTIME_ID clock (Linux only)'
-  Print *,'' 
   sum    = 0.0_WP
   time_e = 0.0_WP
   time_s = 0.0_WP
@@ -76,12 +79,10 @@ Program test_timers
   End Do 
   Call timer_cgt(time_e, CLOCK_THREAD_CPUTIME_ID)
   delta = time_e - time_s
-  Write(*,'( " delta time C cgt thread cputime  = ", g0.15)') delta
+  Write(*,'( " C clock_gettime (THREAD_CPUTIME) = ", 1PE22.15," Linux only")') delta 
+  Write(buf,'(1PE22.15)') sum
 #endif
 
-  Print *,'' 
-  Print *,' DATE_AND_TIME'
-  Print *,'' 
   sum    = 0.0_WP
   time_e = 0.0_WP
   time_s = 0.0_WP
@@ -93,11 +94,9 @@ Program test_timers
   End Do 
   Call timer_dt(time_e)
   delta = time_e - time_s
-  Write(*,'( " delta time DT                    = ", g0.15)') delta 
+  Write(*,'( " DATE_AND_TIME                    = ", 1PE22.15)') delta 
+  Write(buf,'(1PE22.15)') sum
 
-  Print *,'' 
-  Print *,' CPU_TIME'
-  Print *,'' 
   sum    = 0.0_WP
   time_e = 0.0_WP
   time_s = 0.0_WP
@@ -109,11 +108,9 @@ Program test_timers
   End Do 
   Call CPU_TIME(time_e)
   delta = time_e - time_s
-  Write(*,'( " delta time CPU                   = ", g0.15)') delta 
+  Write(*,'( " CPU_TIME                         = ", 1PE22.15)') delta 
+  Write(buf,'(1PE22.15)') sum
 
-  Print *,'' 
-  Print *,' SYSTEM_CLOCK'
-  Print *,'' 
   sum    = 0.0_WP
   time_e = 0.0_WP
   time_s = 0.0_WP
@@ -125,11 +122,11 @@ Program test_timers
   End Do 
   Call timer_sc(time_e)
   delta = time_e - time_s
-  Write(*,'( " delta time SC                    = ", g0.15)') delta
-  Print *,''
+  Write(*,'( " SYSTEM_CLOCK                     = ", 1PE22.15)') delta
+  Write(buf,'(1PE22.15)') sum
 
   Print *,''
-  Print *,' DATE_AND_TIME increment'
+  Print *,'DATE_AND_TIME and SYSTEM_CLOCK increments'
   Print *,''
   time_e = 0.0_WP
   time_s = 0.0_WP
@@ -139,10 +136,7 @@ Program test_timers
     If (time_e > time_s) EXIT
   End Do
   delta = time_e - time_s
-  Write(*,'( " delta time DT increment                    = ", g0.15)') delta
-  Print *,''
-  Print *,' SYSTEM CLOCK increment'
-  Print *,''
+  Write(*,'( " DATE_AND_TIME increment          = ", 1PE22.15)') delta
   time_e = 0.0_WP
   time_s = 0.0_WP
   Call timer_sc(time_s)
@@ -151,8 +145,8 @@ Program test_timers
     If (time_e > time_s) EXIT
   End Do
   delta = time_e - time_s
-  Write(*,'( " delta time SC increment                    = ", g0.15)') delta
- 
+  Write(*,'( " SYSTEM_CLOCK increment           = ", 1PE22.15)') delta
+  Print *,'' 
   Stop
 
 End Program test_timers

timers/timers.F90

@@ -4,13 +4,13 @@ Module timers
   USE ISO_C_BINDING,   ONLY: C_INT, C_LONG, C_PTR, C_NULL_PTR, C_DOUBLE
 
   Implicit NONE
-
+  PRIVATE
 ! Define some clock ids for C clock_gettime function
 
   Integer(C_INT), Parameter :: CLOCK_REALTIME           = 0_C_INT
   Integer(C_INT), Parameter :: CLOCK_MONOTONIC          = 1_C_INT
-#ifdef __linux__ 
 ! These are Linux only
+#ifdef __linux__
   Integer(C_INT), Parameter :: CLOCK_PROCESS_CPUTIME_ID = 2_C_INT
   Integer(C_INT), Parameter :: CLOCK_THREAD_CPUTIME_ID  = 3_C_INT
   Integer(C_INT), Parameter :: CLOCK_TAI                = 11_C_INT
@@ -54,6 +54,16 @@ Function clock_gettime_c(clockid, tp) BIND(C,NAME="clock_gettime")
     End Function clock_gettime_c
   End Interface
 
+  Public :: timer_dt, timer_gtd, timer_cgt, timer_sc
+  Public :: CLOCK_REALTIME
+  Public :: CLOCK_MONOTONIC
+! These are Linux only
+#ifdef __linux__
+  Public :: CLOCK_PROCESS_CPUTIME_ID
+  Public :: CLOCK_THREAD_CPUTIME_ID
+  Public :: CLOCK_TAI
+#endif
+
 Contains
 
   Subroutine timer_dt(time)