[PATCH] Allow trace data to stay CPU endianness

Basically just check whether we need to convert the trace or not
in blkparse, then we can get rid of the endianness conversion
in the hot path (blktrace:write_tip_events()).

1 files changed, 27 insertions, 16 deletions

diff --git a/blktrace.h b/blktrace.h
index af5ab66..13d6e03 100644
--- a/blktrace.h
+++ b/blktrace.h
@@ -53,6 +53,7 @@ struct per_cpu_info {
 };
 
 extern FILE *ofp;
+extern int data_is_native;
 
 #define CHECK_MAGIC(t)		(((t)->magic & 0xffffff00) == BLK_IO_TRACE_MAGIC)
 #define SUPPORTED_VERSION	(0x06)
@@ -90,24 +91,11 @@ static inline int verify_trace(struct blk_io_trace *t)
 	return 0;
 }
 
-static inline void trace_to_be(struct blk_io_trace *t)
-{
-	t->magic	= cpu_to_be32(t->magic);
-	t->sequence	= cpu_to_be32(t->sequence);
-	t->time		= cpu_to_be64(t->time);
-	t->sector	= cpu_to_be64(t->sector);
-	t->bytes	= cpu_to_be32(t->bytes);
-	t->action	= cpu_to_be32(t->action);
-	t->pid		= cpu_to_be32(t->pid);
-	t->cpu		= cpu_to_be32(t->cpu);
-	t->error	= cpu_to_be16(t->error);
-	t->pdu_len	= cpu_to_be16(t->pdu_len);
-	t->device	= cpu_to_be32(t->device);
-	/* t->comm is a string (endian neutral) */
-}
-
 static inline void trace_to_cpu(struct blk_io_trace *t)
 {
+	if (data_is_native)
+		return;
+
 	t->magic	= be32_to_cpu(t->magic);
 	t->sequence	= be32_to_cpu(t->sequence);
 	t->time		= be64_to_cpu(t->time);
@@ -122,6 +110,29 @@ static inline void trace_to_cpu(struct blk_io_trace *t)
 	/* t->comm is a string (endian neutral) */
 }
 
+/*
+ * check whether data is native or not
+ */
+static inline int check_data_endianness(struct blk_io_trace *bit)
+{
+	u32 magic;
+
+	if ((bit->magic & 0xffffff00) == BLK_IO_TRACE_MAGIC) {
+		fprintf(stderr, "data is native\n");
+		data_is_native = 1;
+		return 0;
+	}
+
+	magic = __bswap_32(bit->magic);
+	if ((magic & 0xffffff00) == BLK_IO_TRACE_MAGIC) {
+		fprintf(stderr, "data is not native\n");
+		data_is_native = 0;
+		return 0;
+	}
+
+	return 1;
+}
+
 extern void set_all_format_specs(char *);
 extern int add_format_spec(char *);
 extern void process_fmt(char *, struct per_cpu_info *, struct blk_io_trace *,