Use funcptr, inited from __wt_library_init.

Alphabetize and other cleanup.  refs #582

3 files changed, 35 insertions, 63 deletions

diff --git a/src/include/extern.h b/src/include/extern.h
index 1ef100c6ef9..d4abcf3615b 100644
--- a/src/include/extern.h
+++ b/src/include/extern.h
@@ -1169,6 +1169,7 @@ extern int __wt_session_discard_btree( WT_SESSION_IMPL *session,
     WT_DATA_HANDLE_CACHE *dhandle_cache);
 extern int __wt_salvage(WT_SESSION_IMPL *session, const char *cfg[]);
 extern uint32_t __wt_cksum(const void *chunk, size_t len);
+extern void __wt_cksum_init();
 extern void __wt_event_handler_set(WT_SESSION_IMPL *session,
     WT_EVENT_HANDLER *handler);
 extern void __wt_err(WT_SESSION_IMPL *session,
diff --git a/src/support/cksum.c b/src/support/cksum.c
index b6fd45072cf..383b899b9ab 100644
--- a/src/support/cksum.c
+++ b/src/support/cksum.c
@@ -26,39 +26,20 @@
  */
 
 #include "wt_internal.h"
-#include <stddef.h>
-#include <stdint.h>
-
-#define	CRC_HARDWARE_UNKNOWN	0
-#define	CRC_HARDWARE_PRESENT	1
-#define	CRC_HARDWARE_ABSENT	2
 
 /*
- * This file contains two ways of computing CRC: one that uses a hardware CRC
- * instruction (only on newer x86_64/amd64), and one that uses a fast software
- * algorithm.  __wt_cksum() provides a common entry point that uses one of these
- * two methods.
- *
- * To take advantage of the CRC hardware instruction, we detect it using
- * get_cpuid() on the first call to __wt_cksum().  Using runtime detection with
- * get_cpuid allows for single compatible binary that can be used across all
- * x86_64/amd64 processors, even those without the CRC hardware.
- *
- * If we do not have CPUID, or if the detection fails to find hardware CRC,
- * we'll use a software algorithm as a fallback.
+ * This file contains two implementations for computing CRC: one that uses
+ * hardware CRC instructions, available on newer x86_64/amd64, and one that uses
+ * a fast software algorithm.  __wt_cksum() provides a common entry point that
+ * indirects to one of these two methods.
  */
-#undef TEST_CRC_HARDWARE
-#if (defined(__amd64) || defined(__x86_64))
-#define	CRC_HARDWARE_DEFAULT CRC_HARDWARE_UNKNOWN
-#define	TEST_CRC_HARDWARE
-#else
-#define	CRC_HARDWARE_DEFAULT CRC_HARDWARE_ABSENT
-#endif
+static uint32_t __wt_cksum_sw(const void *chunk, size_t len);
+static uint32_t __wt_cksum_hw(const void *chunk, size_t len);
 
-static volatile int crc_hardware_check = CRC_HARDWARE_DEFAULT;
+static uint32_t (*__wt_cksum_func)(const void *chunk, size_t len);
 
 /*
- * The CRC slicing tables are used by cksum_sw.
+ * The CRC slicing tables are used by __wt_cksum_sw.
  */
 static const uint32_t g_crc_slicing[8][256] = {
 #ifdef WORDS_BIGENDIAN
@@ -1113,7 +1094,7 @@ static const uint32_t g_crc_slicing[8][256] = {
 };
 
 /*
- * cksum_sw --
+ * __wt_cksum_sw --
  *	Return a checksum for a chunk of memory, computed in software.
  *
  * Slicing-by-8 algorithm by Michael E. Kounavis and Frank L. Berry from
@@ -1128,7 +1109,7 @@ static const uint32_t g_crc_slicing[8][256] = {
  * little endian.
  */
 static uint32_t
-cksum_sw(const void *chunk, size_t len)
+__wt_cksum_sw(const void *chunk, size_t len)
 {
 	uint32_t crc, next;
 	size_t nqwords;
@@ -1192,14 +1173,14 @@ cksum_sw(const void *chunk, size_t len)
 	return (~crc);
 }
 
-#ifdef TEST_CRC_HARDWARE
+#if (defined(__amd64) || defined(__x86_64))
 /*
- * cksum_hw --
+ * __wt_cksum_hw --
  *	Return a checksum for a chunk of memory, computed in hardware
  *	using 8 byte steps.
  */
 static uint32_t
-cksum_hw(const void *chunk, size_t len)
+__wt_cksum_hw(const void *chunk, size_t len)
 {
 	uint32_t crc;
 	size_t nqwords;
@@ -1238,15 +1219,28 @@ cksum_hw(const void *chunk, size_t len)
 	}
 	return (~crc);
 }
+#endif
+
+/*
+ * __wt_cksum --
+ *	Return a checksum for a chunk of memory
+ *	using the fastest method available.
+ */
+uint32_t
+__wt_cksum(const void *chunk, size_t len)
+{
+	return (*__wt_cksum_func)(chunk, len);
+}
 
 /*
- * detect_crc_hardware --
+ * __wt_cksum_init --
  *	Detect CRC hardware if possible, and return one of
  *	CRC_HARDWARE_PRESENT or CRC_HARDWARE_ABSENT.
  */
-static int
-detect_crc_hardware(void)
+void
+__wt_cksum_init()
 {
+#if (defined(__amd64) || defined(__x86_64))
 	unsigned int eax, ebx, ecx, edx;
 
 	__asm__ __volatile__ (
@@ -1257,35 +1251,11 @@ detect_crc_hardware(void)
 #define	CPUID_ECX_HAS_SSE42	(1 << 20)
 
 	if (ecx & CPUID_ECX_HAS_SSE42)
-		return (CRC_HARDWARE_PRESENT);
-	return (CRC_HARDWARE_ABSENT);
-}
-#endif
-
-/*
- * __wt_cksum --
- *	Return a checksum for a chunk of memory
- *	using the fastest method available.
- */
-uint32_t
-__wt_cksum(const void *chunk, size_t len)
-{
-#ifdef TEST_CRC_HARDWARE
-	uint32_t result;
+		__wt_cksum_func = __wt_cksum_hw;
+	else
+		__wt_cksum_func = __wt_cksum_sw;
 
-	if (crc_hardware_check == CRC_HARDWARE_UNKNOWN)
-		crc_hardware_check = detect_crc_hardware();
-
-	switch (crc_hardware_check) {
-	case CRC_HARDWARE_PRESENT:
-		result = cksum_hw(chunk, len);
-		break;
-	default:
-		result = cksum_sw(chunk, len);
-		break;
-	}
-	return (result);
 #else
-	return (cksum_sw(chunk, len));
+	__wt_cksum_func = __wt_cksum_sw;
 #endif
 }
diff --git a/src/support/global.c b/src/support/global.c
index 644b5c19a94..1afd5de6d2f 100644
--- a/src/support/global.c
+++ b/src/support/global.c
@@ -32,6 +32,7 @@ static void
 __wt_pthread_once(void)
 {
 	__wt_spin_init(NULL, &__wt_process.spinlock);
+	__wt_cksum_init();
 
 	TAILQ_INIT(&__wt_process.connqh);