Enabled usage of crc32hw in WAL writer; style corrections in cpu_feature.

core/cpu_feature.m

@@ -32,14 +32,14 @@ enum { eAX=0, eBX, eCX, eDX };
 
 static const struct cpuid_feature {
 	unsigned int 	ri;
-	u_int32_t 		mask;
-} cpu_ftr[] = {
+	u_int32_t	bitmask;
+} cpu_mask[] = {
 	{eDX, (1 << 28)},	/* HT 		*/
 	{eCX, (1 << 19)},	/* SSE 4.1 	*/
 	{eCX, (1 << 20)},	/* SSE 4.2 	*/
 	{eCX, (1 << 31)}	/* HYPERV	*/
 };
-static const size_t LEN_cpu_ftr = sizeof(cpu_ftr) / sizeof (cpu_ftr[0]);
+static const size_t LEN_cpu_mask = sizeof(cpu_mask) / sizeof (cpu_mask[0]);
 
 #define SCALE_F		sizeof(unsigned long)
 
@@ -52,8 +52,9 @@ static const size_t LEN_cpu_ftr = sizeof(cpu_ftr) / sizeof (cpu_ftr[0]);
 #endif
 
 
-/* hw-calculate CRC32 per byte (for the unaligned portion of data buffer)
- */
+/* Hw-calculate CRC32 per byte (for the unaligned portion of data buffer). */
+/* NOTE: the function below was adopted from Linux 2.6 kernel source tree,
+   licensed under GPL. */
 static u_int32_t
 crc32c_hw_byte(u_int32_t crc, unsigned char const *data, size_t length)
 {
@@ -70,14 +71,15 @@ crc32c_hw_byte(u_int32_t crc, unsigned char const *data, size_t length)
 }
 
 
-/* hw-calculate CRC32 for the given data buffer
- */
-u_int32_t
-crc32c_hw(u_int32_t crc, unsigned char const *p, size_t len)
+/* Hw-calculate CRC32 for the given data buffer.  */
+/* NOTE: the function below was adopted from Linux 2.6 kernel source tree,
+   licensed under GPL. */
+static u_int32_t
+crc32c_hw_intel(u_int32_t crc, unsigned char const *buf, size_t len)
 {
 	unsigned int iquotient = len / SCALE_F;
 	unsigned int iremainder = len % SCALE_F;
-	unsigned long *ptmp = (unsigned long *)p;
+	unsigned long *ptmp = (unsigned long *)buf;
 
 	while (iquotient--) {
 		__asm__ __volatile__(
@@ -97,9 +99,14 @@ crc32c_hw(u_int32_t crc, unsigned char const *p, size_t len)
 }
 
 
-/* toggle x86 flag-register bits, as per mask
-   return flags both in original and toggled state
- */
+u_int32_t
+crc32c_hw(u_int32_t crc, const unsigned char *buf, unsigned int len)
+{
+	return crc32c_hw_intel (crc, (unsigned char const*)buf, len);
+}
+
+
+/* Toggle x86 flag-register bits, as per mask. */
 static void
 toggle_x86_flags (long mask, long* orig, long* toggled)
 {
@@ -127,7 +134,7 @@ toggle_x86_flags (long mask, long* orig, long* toggled)
 }
 
 
-/* is CPUID instruction available ? */
+/* Is CPUID instruction available ? */
 static int
 can_cpuid ()
 {
@@ -140,15 +147,15 @@ can_cpuid ()
 	};
 
 
-	/* check if AC (alignment) flag could be toggled:
-		if not - it's i386, thus no CPUID
+	/* Check if AC (alignment) flag could be toggled:
+		if not - it's i386, thus no CPUID.
 	*/
 	toggle_x86_flags (cpuf_AC, &of, &tf);
 	if ((of & cpuf_AC) == (tf & cpuf_AC)) {
 		return 0;
 	}
 
-	/* next try toggling CPUID (ID) flag */
+	/* Next try toggling CPUID (ID) flag. */
 	toggle_x86_flags (cpuf_ID, &of, &tf);
 	if ((of & cpuf_ID) == (tf & cpuf_ID)) {
 		return 0;
@@ -158,7 +165,7 @@ can_cpuid ()
 }
 
 
-/* retrieve CPUID data using info as the EAX key */
+/* Retrieve CPUID data using info as the EAX key. */
 static void
 get_cpuid (long info, long* eax, long* ebx, long* ecx, long *edx)
 {
@@ -183,7 +190,7 @@ get_cpuid (long info, long* eax, long* ebx, long* ecx, long *edx)
 }
 
 
-/* return 1=feature is available, 0=unavailable, 0>(errno) = error */
+/* Check whether CPU has a certain feature. */
 int
 cpu_has (unsigned int feature)
 {
@@ -192,12 +199,12 @@ cpu_has (unsigned int feature)
 	if (!can_cpuid ())
 		return -EINVAL;
 
-	if (feature > LEN_cpu_ftr)
+	if (feature > LEN_cpu_mask)
 		return -ERANGE;
 
 	get_cpuid (info, &reg[eAX], &reg[eBX], &reg[eCX], &reg[eDX]);
 
-	return (reg[cpu_ftr[feature].ri] & cpu_ftr[feature].mask) ? 1 : 0;
+	return (reg[cpu_mask[feature].ri] & cpu_mask[feature].bitmask) ? 1 : 0;
 }
 
 

core/log_io.m

@@ -43,6 +43,7 @@
 #include <say.h>
 #include <third_party/crc32.h>
 #include <pickle.h>
+#include <cpu_feature.h>
 
 const u16 snap_tag = -1;
 const u16 wal_tag = -2;
@@ -61,6 +62,11 @@ const char *xlog_mark = "XLOG\n";
 
 static struct tbuf *row_reader_v11(FILE *f, struct palloc_pool *pool);
 
+/* Will be set to either HW or SW CRC32 calculation routine depending on CPU
+   capabilities. */
+static u_int32_t (*calc_crc32c)(u_int32_t crc, const unsigned char *buf,
+				unsigned int len) = NULL;
+
 struct log_io_iter {
 	struct tarantool_coro coro;
 	struct log_io *log;
@@ -1235,9 +1241,9 @@ write_to_disk(void *_state, struct tbuf *t)
 	row_v11(header)->tm = ev_now();
 	row_v11(header)->len = wal_write_request(t)->len;
 	row_v11(header)->data_crc32c =
-		crc32c(0, wal_write_request(t)->data, wal_write_request(t)->len);
+		calc_crc32c(0, wal_write_request(t)->data, wal_write_request(t)->len);
 	row_v11(header)->header_crc32c =
-		crc32c(0, header->data + field_sizeof(struct row_v11, header_crc32c),
+		calc_crc32c(0, header->data + field_sizeof(struct row_v11, header_crc32c),
 		       sizeof(struct row_v11) - field_sizeof(struct row_v11, header_crc32c));
 
 	if (fwrite(header->data, header->size, 1, wal->f) != 1) {
@@ -1331,6 +1337,8 @@ recover_init(const char *snap_dirname, const char *wal_dirname,
 	r->wal_class->fsync_delay = fsync_delay;
 	wait_lsn_clear(&r->wait_lsn);
 
+	calc_crc32c = cpu_has (cpuf_sse4_2) ? &crc32c_hw : &crc32c;
+
 	if ((flags & RECOVER_READONLY) == 0)
 		r->wal_writer = spawn_child("wal_writer", inbox_size, write_to_disk, r);
 

include/cpu_feature.h

@@ -27,22 +27,31 @@
 
 #include <sys/types.h>
 
-/* CPU feature capabilities to use with cpu_has (feature) */
+/* CPU feature capabilities to use with cpu_has (feature). */
 enum {
 	cpuf_ht = 0, cpuf_sse4_1, cpuf_sse4_2, cpuf_hypervisor
 };
 
-/*	return 1=feature is available, 0=unavailable, -EINVAL = unsupported CPU,
-	-ERANGE = invalid feature
-*/
+/* Check whether CPU has a certain feature.
+ *
+ * @param	feature		indetifier (see above) of the target feature
+ *
+ * @return	1 if feature is available, 0 if unavailable,
+ *		-EINVAL if unsupported CPU, -ERANGE if invalid feature
+ */
 int cpu_has (unsigned int feature);
 
 
-/* hardware-calculate CRC32 for the given data buffer
- * NB: 	requires 1 == cpu_has (cpuf_sse4_2),
- * 		CALLING IT W/O CHECKING for sse4_2 CAN CAUSE SIGABRT
+/* Hardware-calculate CRC32 for the given data buffer.
+ *
+ * @param	crc 		initial CRC
+ * @param	buf			data buffer
+ * @param	len			buffer length
+ *
+ * @pre 	1 == cpu_has (cpuf_sse4_2)
+ * @return	CRC32 value
  */
-u_int32_t crc32c_hw(u_int32_t crc, unsigned char const *p, size_t len);
+u_int32_t crc32c_hw(u_int32_t crc, const unsigned char *buf, unsigned int len);
 
 
 #endif /* TARANTOOL_CPU_FEATURES_H */