Begin libsandglass implementation.

7 files changed, 368 insertions, 10 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 4fc85ab..476c855 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -21,7 +21,7 @@ lib_LTLIBRARIES = libsandglass.la
 
 nobase_include_HEADERS = sandglass.h
 
-libsandglass_la_SOURCES    = sandglass.h sandglass.c
+libsandglass_la_SOURCES    = sandglass.h sandglass_impl.h sandglass.c tsc.c
 
 if X86
   libsandglass_la_SOURCES += x86/tsc-x86.s
@@ -30,3 +30,5 @@ endif
 if X86_64
   libsandglass_la_SOURCES += x86_64/tsc-x86_64.s
 endif
+
+libsandglass_la_LIBADD     = -lrt
diff --git a/src/sandglass.c b/src/sandglass.c
index 4acf983..57729f9 100644
--- a/src/sandglass.c
+++ b/src/sandglass.c
@@ -18,4 +18,253 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
+#include "sandglass_impl.h"
 #include "sandglass.h"
+#include <unistd.h>
+#include <time.h>
+#include <errno.h>
+
+static int sandglass_real_create(sandglass_t *sandglass,
+                                 const sandglass_attributes_t *attr);
+
+/* Create a timer */
+int
+sandglass_create(sandglass_t *sandglass,
+                 const sandglass_attributes_t *min,
+                 const sandglass_attributes_t *max)
+{
+  sandglass_attributes_t realmin, realmax;
+
+  /* Get our real min and max values */
+
+  if (min)
+    realmin = *min;
+  else {
+    /* min defaults to { SANDGLASS_INTROSPECTIVE, SANDGLASS_SYSTEM } */
+    realmin.incrementation = SANDGLASS_INTROSPECTIVE;
+    realmin.resolution     = SANDGLASS_SYSTEM;
+  }
+
+  if (max)
+    realmax = *max;
+  else {
+    /* max defaults to the greater of min and { SANDGLASS_INTROSPECTIVE,
+       SANDGLASS_CPUTIME } */
+    if (realmin.incrementation > SANDGLASS_INTROSPECTIVE
+        || (realmin.incrementation == SANDGLASS_INTROSPECTIVE
+            && realmin.resolution > SANDGLASS_CPUTIME))
+      realmax = realmin;
+    else {
+      realmax.incrementation = SANDGLASS_INTROSPECTIVE;
+      realmax.resolution     = SANDGLASS_CPUTIME;
+    }
+  }
+
+  /* Ensure max >= min */
+  if (realmax.incrementation < realmin.incrementation
+      || (realmax.incrementation == realmin.incrementation
+          && realmax.resolution < realmin.resolution))
+  {
+    errno = EINVAL;
+    return -1;
+  }
+
+  /* Now search for available timers, starting from max */
+
+  while (sandglass_real_create(sandglass, &realmax) != 0) {
+    /* Once we reach the minimum attributes, bail out */
+    if (realmax.incrementation == realmin.incrementation
+        && realmax.resolution == realmin.resolution)
+    {
+      errno = ENOTSUP;
+      return -1;
+    }
+
+    /* Try the next lowest allowable settings */
+    if (realmax.resolution)
+      --realmax.resolution;
+    else {
+      if (realmax.incrementation) {
+        --realmax.incrementation;
+        realmax.resolution = SANDGLASS_CPUTIME;
+      } else {
+        errno = ENOTSUP;
+        return -1;
+      }
+    }
+  }
+
+  return 0;
+}
+
+static int
+sandglass_real_create(sandglass_t *sandglass,
+                      const sandglass_attributes_t *attr)
+{
+  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;
+          break;
+#else
+          return -1;
+#endif
+
+        case SANDGLASS_SYSTEM:
+          sandglass->resolution = 1e9;
+          sandglass->loops      = 1;
+          break;
+
+        default:
+          return -1;
+      }
+      break;
+
+    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;
+            sandglass->loops      = 1;
+          } else
+            return -1;
+          break;
+
+        case SANDGLASS_SYSTEM:
+          sandglass->resolution = CLOCKS_PER_SEC;
+          sandglass->loops      = 1;
+          break;
+
+        default:
+          return -1;
+      }
+      break;
+
+    default:
+      return -1;
+  }
+
+  sandglass->attributes = *attr;
+  return 0;
+}
+
+/* Store a timer value in sandglass->grains */
+static int sandglass_real_gettime(sandglass_t *sandglass);
+
+/* Start timing */
+int
+sandglass_begin(sandglass_t *sandglass)
+{
+  return sandglass_real_gettime(sandglass);
+}
+
+/* Finish timing */
+int
+sandglass_elapse(sandglass_t *sandglass)
+{
+  long oldgrains = sandglass->grains;
+
+  if (sandglass_real_gettime(sandglass) != 0)
+    return -1;
+
+  sandglass->grains -= oldgrains;
+  sandglass->grains /= sandglass->loops;
+
+  return 0;
+}
+
+/* Store a timer value in sandglass->grains */
+static int
+sandglass_real_gettime(sandglass_t *sandglass)
+{
+  struct timespec ts;
+  clock_t clock_ticks;
+
+  switch (sandglass->attributes.incrementation) {
+    case SANDGLASS_MONOTONIC:
+      switch (sandglass->attributes.resolution) {
+        case SANDGLASS_REALTICKS:
+#ifdef SANDGLASS_TSC
+          sandglass->grains = sandglass_get_tsc();
+          break;
+#else
+          return -1;
+#endif
+
+        case SANDGLASS_CPUTIME:
+#ifdef SANDGLASS_TSC
+          sandglass->grains = sandglass_get_tsc();
+          break;
+#else
+          return -1;
+#endif
+
+        case SANDGLASS_SYSTEM:
+          if (sysconf(_SC_MONOTONIC_CLOCK) > 0) {
+            if (clock_gettime(CLOCK_MONOTONIC, &ts) != 0)
+              return -1;
+            sandglass->grains = ts.tv_nsec;
+          } else {
+            if (clock_gettime(CLOCK_REALTIME, &ts) != 0)
+              return -1;
+            sandglass->grains = ts.tv_nsec;
+          }
+          break;
+
+        default:
+          return -1;
+      }
+      break;
+
+    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)
+              return -1;
+            sandglass->grains = ts.tv_nsec;
+          } else if (sysconf(_SC_CPUTIME) > 0) {
+            if (clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts) != 0)
+              return -1;
+            sandglass->grains = ts.tv_nsec;
+          } else
+            return -1;
+          break;
+
+        case SANDGLASS_SYSTEM:
+          if ((clock_ticks = clock()) == -1)
+            return -1;
+          sandglass->grains = clock();
+          break;
+
+        default:
+          return -1;
+      }
+      break;
+
+    default:
+      return -1;
+  }
+
+  return 0;
+}
diff --git a/src/sandglass.h b/src/sandglass.h
index a9e99e5..3cd14ba 100644
--- a/src/sandglass.h
+++ b/src/sandglass.h
@@ -93,7 +93,7 @@ struct sandglass_t
   long grains;
 
   /* grains/resolution should give elapsed time in seconds */
-  long resolution;
+  double resolution;
 
   /*
    * Internal fields
@@ -140,20 +140,15 @@ int sandglass_elapse(sandglass_t *sandglass);
   do {                                                                         \
     routine;                                                                   \
     sandglass_begin(sandglass);                                                \
-    for ((sandglass)->i = 0; (sandglass)->i < (sandglass)->loops; ++i) {       \
+    for ((sandglass)->i = 0;                                                   \
+         (sandglass)->i < (sandglass)->loops;                                  \
+         ++(sandglass)->i) {                                                   \
       SANDGLASS_NO_UNROLL();                                                   \
       routine;                                                                 \
     }                                                                          \
     sandglass_elapse(sandglass);                                               \
   } while (0)
 
-/*
- * Low-level API
- */
-
-/* Read the time stamp counter */
-long sandglass_get_tsc();
-
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/sandglass_impl.h b/src/sandglass_impl.h
new file mode 100644
index 0000000..5a3650e
--- /dev/null
+++ b/src/sandglass_impl.h
@@ -0,0 +1,39 @@
+/*************************************************************************
+ * Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com>               *
+ *                                                                       *
+ * This file is part of The Sandglass Library.                           *
+ *                                                                       *
+ * The Sandglass Library is free software; you can redistribute it       *
+ * and/or modify it under the terms of the GNU Lesser General Public     *
+ * License as published by the Free Software Foundation; either version  *
+ * 3 of the License, or (at your option) any later version.              *
+ *                                                                       *
+ * The Sandglass Library is distributed in the hope that it will be      *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+/*
+ * Internal libsandglass API
+ */
+
+#ifndef SANDGLASS_IMPL_H_INCLUDED
+#define SANDGLASS_IMPL_H_INCLUDED
+
+#include "sandglass.h"
+
+#ifdef SANDGLASS_TSC
+/* Read the time stamp counter */
+long sandglass_get_tsc();
+/* Get the timing resolution of the TSC */
+double sandglass_tsc_resolution();
+/* Get the necessary number of loops for SANDGLASS_REALTICKS */
+unsigned int sandglass_tsc_loops();
+#endif
+
+#endif /* SANDGLASS_IMPL_H_INCLUDED */
\ No newline at end of file
diff --git a/src/tsc.c b/src/tsc.c
new file mode 100644
index 0000000..64fe1b1
--- /dev/null
+++ b/src/tsc.c
@@ -0,0 +1,39 @@
+/*************************************************************************
+ * Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com>               *
+ *                                                                       *
+ * This file is part of The Sandglass Library.                           *
+ *                                                                       *
+ * The Sandglass Library is free software; you can redistribute it       *
+ * and/or modify it under the terms of the GNU Lesser General Public     *
+ * License as published by the Free Software Foundation; either version  *
+ * 3 of the License, or (at your option) any later version.              *
+ *                                                                       *
+ * The Sandglass Library is distributed in the hope that it will be      *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+#include "sandglass_impl.h"
+#include "sandglass.h"
+#include <time.h>
+
+/* Gets the number of clock ticks per second */
+double
+sandglass_tsc_resolution()
+{
+  static long tsc = 0;
+  struct timespec ts = { .tv_sec = 0, .tv_nsec = 100000000 };
+
+  if (tsc == 0) {
+    tsc = sandglass_get_tsc();
+    while (nanosleep(&ts, &ts) != 0);
+    tsc = sandglass_get_tsc() - tsc;
+  }
+
+  return tsc*10.0;
+}
diff --git a/src/x86/tsc-x86.s b/src/x86/tsc-x86.s
index 570b8af..46013bb 100644
--- a/src/x86/tsc-x86.s
+++ b/src/x86/tsc-x86.s
@@ -38,3 +38,20 @@ sandglass_get_tsc:
         popl %ebx
         ret
         .size sandglass_get_tsc, .-sandglass_get_tsc
+
+/*
+ * Return the granularity of the TSC
+ */
+
+/* unsigned int sandglass_tsc_loops(); */
+.globl sandglass_tsc_loops
+        .type sandglass_tsc_loops, @function
+sandglass_tsc_loops:
+        rdtsc                   /* Read time stamp counter */
+        movl %eax, %ecx
+.Lrdtsc:
+        rdtsc                   /* Read counter again */
+        subl %ecx, %eax
+        jz .Lrdtsc              /* If we got the same value, try again */
+        ret
+        .size sandglass_tsc_loops, .-sandglass_tsc_loops
diff --git a/src/x86_64/tsc-x86_64.s b/src/x86_64/tsc-x86_64.s
index c585719..52f02c2 100644
--- a/src/x86_64/tsc-x86_64.s
+++ b/src/x86_64/tsc-x86_64.s
@@ -38,3 +38,20 @@ sandglass_get_tsc:
         movq %rdi, %rbx
         ret
         .size sandglass_get_tsc, .-sandglass_get_tsc
+
+/*
+ * Return the granularity of the TSC
+ */
+
+/* unsigned int sandglass_tsc_loops(); */
+.globl sandglass_tsc_loops
+        .type sandglass_tsc_loops, @function
+sandglass_tsc_loops:
+        rdtsc                   /* Read time stamp counter */
+        movl %eax, %ecx
+.Lrdtsc:
+        rdtsc                   /* Read counter again */
+        subl %ecx, %eax
+        jz .Lrdtsc              /* If we got the same value, try again */
+        ret
+        .size sandglass_tsc_loops, .-sandglass_tsc_loops