New sandglass_bench_* macros, remove SANDGLASS_REALTICKS.

sandglass_bench_fine() replaces SANDGLASS_REALTICKS; use SANDGLASS_CPUTIME
instead.  Also, sandglass_bench_noprecache() for when the expression to be
timed has side-effects and should be executed only once.

4 files changed, 59 insertions, 181 deletions

diff --git a/src/sandglass.c b/src/sandglass.c
index 6db28a3..f97b9c1 100644
--- a/src/sandglass.c
+++ b/src/sandglass.c
@@ -104,19 +104,10 @@ sandglass_real_create(sandglass_t *sandglass,
   switch (attr->incrementation) {
     case SANDGLASS_MONOTONIC:
       switch (attr->resolution) {
-        case SANDGLASS_REALTICKS:
-#ifdef SANDGLASS_TSC
-          sandglass->resolution = sandglass_tsc_resolution();
-          sandglass->loops      = sandglass_tsc_loops();
-          break;
-#else
-          return -1;
-#endif
-
         case SANDGLASS_CPUTIME:
 #ifdef SANDGLASS_TSC
           sandglass->resolution = sandglass_tsc_resolution();
-          sandglass->loops      = 1;
+          sandglass->loops      = sandglass_tsc_loops();
           break;
 #else
           return -1;
@@ -134,10 +125,6 @@ sandglass_real_create(sandglass_t *sandglass,
 
     case SANDGLASS_INTROSPECTIVE:
       switch (attr->resolution) {
-        case SANDGLASS_REALTICKS:
-          /* No such thing as an introspective raw TSC */
-          return -1;
-
         case SANDGLASS_CPUTIME:
           if (sysconf(_SC_THREAD_CPUTIME) > 0 || sysconf(_SC_CPUTIME) > 0) {
             sandglass->resolution = 1e9;
@@ -202,7 +189,6 @@ sandglass_real_gettime(sandglass_t *sandglass)
   switch (sandglass->attributes.incrementation) {
     case SANDGLASS_MONOTONIC:
       switch (sandglass->attributes.resolution) {
-        case SANDGLASS_REALTICKS:
         case SANDGLASS_CPUTIME:
 #ifdef SANDGLASS_TSC
           sandglass->grains = sandglass_get_tsc();
@@ -230,10 +216,6 @@ sandglass_real_gettime(sandglass_t *sandglass)
 
     case SANDGLASS_INTROSPECTIVE:
       switch (sandglass->attributes.resolution) {
-        case SANDGLASS_REALTICKS:
-          /* No such thing as an introspective raw TSC */
-          return -1;
-
         case SANDGLASS_CPUTIME:
           if (sysconf(_SC_THREAD_CPUTIME) > 0) {
             if (clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts) != 0)
diff --git a/src/sandglass.h b/src/sandglass.h
index 0d5e5e5..34461ba 100644
--- a/src/sandglass.h
+++ b/src/sandglass.h
@@ -26,6 +26,8 @@
 #ifndef SANDGLASS_H_INCLUDED
 #define SANDGLASS_H_INCLUDED
 
+#include <assert.h>
+
 #ifdef __cplusplus
 /* We've been included from a C++ file; mark everything here as extern "C" */
 extern "C" {
@@ -65,14 +67,7 @@ enum sandglass_resolution_t
    * portable.  Uses the CLOCK_THREAD_CPUTIME_ID clock for
    * SANDGLASS_INTROSPECTIVE mode, and the raw TSC for SANDGLASS_MONOTONIC.
    */
-  SANDGLASS_CPUTIME,
-
-  /*
-   * Get timing information accurate to within one CPU clock cycle - requires
-   * some looping and other trickery to account for TSCs which are not accurate
-   * to within one clock cycle.  Not valid with SANDGLASS_INTROSPECTIVE.
-   */
-  SANDGLASS_REALTICKS
+  SANDGLASS_CPUTIME
 };
 typedef enum sandglass_resolution_t sandglass_resolution_t;
 
@@ -134,16 +129,18 @@ int sandglass_elapse(sandglass_t *sandglass);
 #define SANDGLASS_NO_UNROLL() __asm__ __volatile__ ("")
 
 /*
- * Macro to facilitate correct benchmarking of blocks of code.  May be called
+ * Macros to facilitate correct benchmarking of blocks of code.  May be called
  * like so:
- *   sandglass_bench(&sandglass, f(x))
+ *   sandglass_bench*(&sandglass, f(x))
  * or like so:
- *   sandglass_bench(&sandglass, {
+ *   sandglass_bench*(&sandglass, {
  *     f(x);
  *     g(x);
  *   });
  */
-#define sandglass_bench(sandglass, routine)                                    \
+
+/* Provides single clock cycle resolution in some cases */
+#define sandglass_bench_fine(sandglass, routine)                               \
   do {                                                                         \
     /* Warm up the cache for these functions */                                \
     sandglass_begin(sandglass);                                                \
@@ -161,6 +158,7 @@ int sandglass_elapse(sandglass_t *sandglass);
                                                                                \
     /* Warm up the cache for our routine */                                    \
     routine;                                                                   \
+                                                                               \
     /* Time our routine in a loop */                                           \
     sandglass_begin(sandglass);                                                \
     for ((sandglass)->i = 0;                                                   \
@@ -168,6 +166,7 @@ int sandglass_elapse(sandglass_t *sandglass);
          ++(sandglass)->i) {                                                   \
       SANDGLASS_NO_UNROLL();                                                   \
       routine;                                                                 \
+      SANDGLASS_NO_UNROLL();                                                   \
     }                                                                          \
     sandglass_elapse(sandglass);                                               \
                                                                                \
@@ -176,6 +175,51 @@ int sandglass_elapse(sandglass_t *sandglass);
     (sandglass)->grains /= (sandglass)->loops;                                 \
   } while (0)
 
+/* General high resolution timer */
+#define sandglass_bench(sandglass, routine)                                    \
+  do {                                                                         \
+    /* Warm up the cache for these functions */                                \
+    sandglass_begin(sandglass);                                                \
+    sandglass_elapse(sandglass);                                               \
+                                                                               \
+    /* Time an empty routine for our baseline */                               \
+    sandglass_begin(sandglass);                                                \
+    sandglass_elapse(sandglass);                                               \
+    (sandglass)->baseline = (sandglass)->grains;                               \
+                                                                               \
+    /* Warm up the cache for our routine */                                    \
+    routine;                                                                   \
+                                                                               \
+    /* Time the routine */                                                     \
+    sandglass_begin(sandglass);                                                \
+    routine;                                                                   \
+    sandglass_elapse(sandglass);                                               \
+                                                                               \
+    /* Subtract the baseline */                                                \
+    (sandglass)->grains -= (sandglass)->baseline;                              \
+  } while (0)
+
+/* Only executes routine once - useful if routine has side-effects */
+#define sandglass_bench_noprecache(sandglass, routine)                         \
+  do {                                                                         \
+    /* Warm up the cache for these functions */                                \
+    sandglass_begin(sandglass);                                                \
+    sandglass_elapse(sandglass);                                               \
+                                                                               \
+    /* Time an empty loop for our baseline */                                  \
+    sandglass_begin(sandglass);                                                \
+    sandglass_elapse(sandglass);                                               \
+    (sandglass)->baseline = (sandglass)->grains;                               \
+                                                                               \
+    /* Time the routine */                                                     \
+    sandglass_begin(sandglass);                                                \
+    routine;                                                                   \
+    sandglass_elapse(sandglass);                                               \
+                                                                               \
+    /* Subtract the baseline */                                                \
+    (sandglass)->grains -= (sandglass)->baseline;                              \
+  } while (0)
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/tests/monotonic-realticks.c b/tests/monotonic-realticks.c
index 9b5daff..51404f5 100644
--- a/tests/monotonic-realticks.c
+++ b/tests/monotonic-realticks.c
@@ -30,14 +30,14 @@ int
 main()
 {
   sandglass_t sandglass;
-  sandglass_attributes_t attr = { SANDGLASS_MONOTONIC, SANDGLASS_REALTICKS };
+  sandglass_attributes_t attr = { SANDGLASS_MONOTONIC, SANDGLASS_CPUTIME };
 
   if (sandglass_create(&sandglass, &attr, &attr) != 0) {
     perror("sandglass_create()");
     return EXIT_FAILURE;
   }
 
-  sandglass_bench(&sandglass, sandglass_get_tsc());
+  sandglass_bench_fine(&sandglass, sandglass_get_tsc());
 
   printf("%ld\n", sandglass.grains);
 
diff --git a/tests/simple-test b/tests/simple-test
deleted file mode 100755
index 8fbcf16..0000000
--- a/tests/simple-test
+++ /dev/null
@@ -1,148 +0,0 @@
-#! /bin/sh
-
-# simple-test - temporary wrapper script for .libs/simple-test
-# Generated by ltmain.sh (GNU libtool) 2.2.6
-#
-# The simple-test program cannot be directly executed until all the libtool
-# libraries that it depends on are installed.
-#
-# This wrapper script should never be moved out of the build directory.
-# If it is, it will not operate correctly.
-
-# Sed substitution that helps us do robust quoting.  It backslashifies
-# metacharacters that are still active within double-quoted strings.
-Xsed='/bin/sed -e 1s/^X//'
-sed_quote_subst='s/\([`"$\\]\)/\\\1/g'
-
-# Be Bourne compatible
-if test -n "${ZSH_VERSION+set}" && (emulate sh) >/dev/null 2>&1; then
-  emulate sh
-  NULLCMD=:
-  # Zsh 3.x and 4.x performs word splitting on ${1+"$@"}, which
-  # is contrary to our usage.  Disable this feature.
-  alias -g '${1+"$@"}'='"$@"'
-  setopt NO_GLOB_SUBST
-else
-  case `(set -o) 2>/dev/null` in *posix*) set -o posix;; esac
-fi
-BIN_SH=xpg4; export BIN_SH # for Tru64
-DUALCASE=1; export DUALCASE # for MKS sh
-
-# The HP-UX ksh and POSIX shell print the target directory to stdout
-# if CDPATH is set.
-(unset CDPATH) >/dev/null 2>&1 && unset CDPATH
-
-relink_command="(cd /home/tavianator/libsandglass/tests; { test -z \"\${LIBRARY_PATH+set}\" || unset LIBRARY_PATH || { LIBRARY_PATH=; export LIBRARY_PATH; }; }; { test -z \"\${COMPILER_PATH+set}\" || unset COMPILER_PATH || { COMPILER_PATH=; export COMPILER_PATH; }; }; { test -z \"\${GCC_EXEC_PREFIX+set}\" || unset GCC_EXEC_PREFIX || { GCC_EXEC_PREFIX=; export GCC_EXEC_PREFIX; }; }; { test -z \"\${LD_RUN_PATH+set}\" || unset LD_RUN_PATH || { LD_RUN_PATH=; export LD_RUN_PATH; }; }; { test -z \"\${LD_LIBRARY_PATH+set}\" || unset LD_LIBRARY_PATH || { LD_LIBRARY_PATH=; export LD_LIBRARY_PATH; }; }; PATH=/bin:/usr/bin:/sbin:/usr/sbin:/opt/java/bin:/opt/java/jre/bin:/home/tavianator/bin:/usr/bin/perlbin/site:/usr/bin/perlbin/vendor:/usr/bin/perlbin/core:/opt/qt/bin; export PATH; gcc -g -Wall -o \$progdir/\$file simple.o  ../src/.libs/libsandglass.so -lrt -Wl,-rpath -Wl,/home/tavianator/libsandglass/src/.libs)"
-
-# This environment variable determines our operation mode.
-if test "$libtool_install_magic" = "%%%MAGIC variable%%%"; then
-  # install mode needs the following variables:
-  generated_by_libtool_version='2.2.6'
-  notinst_deplibs=' ../src/libsandglass.la'
-else
-  # When we are sourced in execute mode, $file and $ECHO are already set.
-  if test "$libtool_execute_magic" != "%%%MAGIC variable%%%"; then
-    ECHO="echo"
-    file="$0"
-    # Make sure echo works.
-    if test "X$1" = X--no-reexec; then
-      # Discard the --no-reexec flag, and continue.
-      shift
-    elif test "X`{ $ECHO '\t'; } 2>/dev/null`" = 'X\t'; then
-      # Yippee, $ECHO works!
-      :
-    else
-      # Restart under the correct shell, and then maybe $ECHO will work.
-      exec /bin/sh "$0" --no-reexec ${1+"$@"}
-    fi
-  fi
-
-  # Find the directory that this script lives in.
-  thisdir=`$ECHO "X$file" | $Xsed -e 's%/[^/]*$%%'`
-  test "x$thisdir" = "x$file" && thisdir=.
-
-  # Follow symbolic links until we get to the real thisdir.
-  file=`ls -ld "$file" | /bin/sed -n 's/.*-> //p'`
-  while test -n "$file"; do
-    destdir=`$ECHO "X$file" | $Xsed -e 's%/[^/]*$%%'`
-
-    # If there was a directory component, then change thisdir.
-    if test "x$destdir" != "x$file"; then
-      case "$destdir" in
-      [\\/]* | [A-Za-z]:[\\/]*) thisdir="$destdir" ;;
-      *) thisdir="$thisdir/$destdir" ;;
-      esac
-    fi
-
-    file=`$ECHO "X$file" | $Xsed -e 's%^.*/%%'`
-    file=`ls -ld "$thisdir/$file" | /bin/sed -n 's/.*-> //p'`
-  done
-
-
-  # Usually 'no', except on cygwin/mingw when embedded into
-  # the cwrapper.
-  WRAPPER_SCRIPT_BELONGS_IN_OBJDIR=no
-  if test "$WRAPPER_SCRIPT_BELONGS_IN_OBJDIR" = "yes"; then
-    # special case for '.'
-    if test "$thisdir" = "."; then
-      thisdir=`pwd`
-    fi
-    # remove .libs from thisdir
-    case "$thisdir" in
-    *[\\/].libs ) thisdir=`$ECHO "X$thisdir" | $Xsed -e 's%[\\/][^\\/]*$%%'` ;;
-    .libs )   thisdir=. ;;
-    esac
-  fi
-
-  # Try to get the absolute directory name.
-  absdir=`cd "$thisdir" && pwd`
-  test -n "$absdir" && thisdir="$absdir"
-
-  program=lt-'simple-test'
-  progdir="$thisdir/.libs"
-
-  if test ! -f "$progdir/$program" ||
-     { file=`ls -1dt "$progdir/$program" "$progdir/../$program" 2>/dev/null | /bin/sed 1q`; \
-       test "X$file" != "X$progdir/$program"; }; then
-
-    file="$$-$program"
-
-    if test ! -d "$progdir"; then
-      mkdir "$progdir"
-    else
-      rm -f "$progdir/$file"
-    fi
-
-    # relink executable if necessary
-    if test -n "$relink_command"; then
-      if relink_command_output=`eval $relink_command 2>&1`; then :
-      else
-	echo "$relink_command_output" >&2
-	rm -f "$progdir/$file"
-	exit 1
-      fi
-    fi
-
-    mv -f "$progdir/$file" "$progdir/$program" 2>/dev/null ||
-    { rm -f "$progdir/$program";
-      mv -f "$progdir/$file" "$progdir/$program"; }
-    rm -f "$progdir/$file"
-  fi
-
-  if test -f "$progdir/$program"; then
-    if test "$libtool_execute_magic" != "%%%MAGIC variable%%%"; then
-      # Run the actual program with our arguments.
-
-      exec "$progdir/$program" ${1+"$@"}
-
-      $ECHO "$0: cannot exec $program $*" 1>&2
-      exit 1
-    fi
-  else
-    # The program doesn't exist.
-    $ECHO "$0: error: \`$progdir/$program' does not exist" 1>&2
-    $ECHO "This script is just a wrapper for $program." 1>&2
-    echo "See the libtool documentation for more information." 1>&2
-    exit 1
-  fi
-fi