From d95b34a61ec3fc305fe53c0132bfe82e2e5fcc04 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Thu, 21 Nov 2013 09:55:49 -0700
Subject: [PATCH 1/1] blktrace: add support for non-native endian format

The blktrace format is stored in the native endianness of
the machine it is run on. So to reply traces on a machine
with a different endianness, we need to swap the trace
fields. Detect and do this automatically.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 blktrace.c | 41 ++++++++++++++++++++++++++++++++++++-----
 fio.h      |  4 ++--
 iolog.c    |  6 ++++--
 os/os.h    |  5 +++--
 4 files changed, 45 insertions(+), 11 deletions(-)

diff --git a/blktrace.c b/blktrace.c
index e195f7f1..04648a08 100644
--- a/blktrace.c
+++ b/blktrace.c
@@ -71,7 +71,7 @@ static int discard_pdu(struct thread_data *td, struct fifo *fifo, int fd,
  * Check if this is a blktrace binary data file. We read a single trace
  * into memory and check for the magic signature.
  */
-int is_blktrace(const char *filename)
+int is_blktrace(const char *filename, int *need_swap)
 {
 	struct blk_io_trace t;
 	int fd, ret;
@@ -91,8 +91,19 @@ int is_blktrace(const char *filename)
 		return 0;
 	}
 
-	if ((t.magic & 0xffffff00) == BLK_IO_TRACE_MAGIC)
+	if ((t.magic & 0xffffff00) == BLK_IO_TRACE_MAGIC) {
+		*need_swap = 0;
 		return 1;
+	}
+
+	/*
+	 * Maybe it needs to be endian swapped...
+	 */
+	t.magic = fio_swap32(t.magic);
+	if ((t.magic & 0xffffff00) == BLK_IO_TRACE_MAGIC) {
+		*need_swap = 1;
+		return 1;
+	}
 
 	return 0;
 }
@@ -245,10 +256,12 @@ static void handle_trace_notify(struct blk_io_trace *t)
 {
 	switch (t->action) {
 	case BLK_TN_PROCESS:
-		printf("got process notify: %x, %d\n", t->action, t->pid);
+		log_info("blktrace: got process notify: %x, %d\n",
+				t->action, t->pid);
 		break;
 	case BLK_TN_TIMESTAMP:
-		printf("got timestamp notify: %x, %d\n", t->action, t->pid);
+		log_info("blktrace: got timestamp notify: %x, %d\n",
+				t->action, t->pid);
 		break;
 	case BLK_TN_MESSAGE:
 		break;
@@ -328,11 +341,26 @@ static void handle_trace(struct thread_data *td, struct blk_io_trace *t,
 		handle_trace_fs(td, t, ttime, ios, bs);
 }
 
+static void byteswap_trace(struct blk_io_trace *t)
+{
+	t->magic = fio_swap32(t->magic);
+	t->sequence = fio_swap32(t->sequence);
+	t->time = fio_swap64(t->time);
+	t->sector = fio_swap64(t->sector);
+	t->bytes = fio_swap32(t->bytes);
+	t->action = fio_swap32(t->action);
+	t->pid = fio_swap32(t->pid);
+	t->device = fio_swap32(t->device);
+	t->cpu = fio_swap32(t->cpu);
+	t->error = fio_swap16(t->error);
+	t->pdu_len = fio_swap16(t->pdu_len);
+}
+
 /*
  * Load a blktrace file by reading all the blk_io_trace entries, and storing
  * them as io_pieces like the fio text version would do.
  */
-int load_blktrace(struct thread_data *td, const char *filename)
+int load_blktrace(struct thread_data *td, const char *filename, int need_swap)
 {
 	unsigned long long ttime, delay;
 	struct blk_io_trace t;
@@ -370,6 +398,9 @@ int load_blktrace(struct thread_data *td, const char *filename)
 			break;
 		}
 
+		if (need_swap)
+			byteswap_trace(&t);
+
 		if ((t.magic & 0xffffff00) != BLK_IO_TRACE_MAGIC) {
 			log_err("fio: bad magic in blktrace data: %x\n",
 								t.magic);
diff --git a/fio.h b/fio.h
index 0d7fbeb9..a6dcb4ea 100644
--- a/fio.h
+++ b/fio.h
@@ -479,8 +479,8 @@ extern void reset_all_stats(struct thread_data *);
  * blktrace support
  */
 #ifdef FIO_HAVE_BLKTRACE
-extern int is_blktrace(const char *);
-extern int load_blktrace(struct thread_data *, const char *);
+extern int is_blktrace(const char *, int *);
+extern int load_blktrace(struct thread_data *, const char *, int);
 #endif
 
 #define for_each_td(td, i)	\
diff --git a/iolog.c b/iolog.c
index 9bcf0d8e..dadbf0fa 100644
--- a/iolog.c
+++ b/iolog.c
@@ -480,12 +480,14 @@ int init_iolog(struct thread_data *td)
 	int ret = 0;
 
 	if (td->o.read_iolog_file) {
+		int need_swap;
+
 		/*
 		 * Check if it's a blktrace file and load that if possible.
 		 * Otherwise assume it's a normal log file and load that.
 		 */
-		if (is_blktrace(td->o.read_iolog_file))
-			ret = load_blktrace(td, td->o.read_iolog_file);
+		if (is_blktrace(td->o.read_iolog_file, &need_swap))
+			ret = load_blktrace(td, td->o.read_iolog_file, need_swap);
 		else
 			ret = init_iolog_read(td);
 	} else if (td->o.write_iolog_file)
diff --git a/os/os.h b/os/os.h
index 715f2260..4b590347 100644
--- a/os/os.h
+++ b/os/os.h
@@ -220,12 +220,13 @@ static inline uint64_t fio_swap64(uint64_t val)
 })
 
 #ifndef FIO_HAVE_BLKTRACE
-static inline int is_blktrace(const char *fname)
+static inline int is_blktrace(const char *fname, int *need_swap)
 {
 	return 0;
 }
 struct thread_data;
-static inline int load_blktrace(struct thread_data *td, const char *fname)
+static inline int load_blktrace(struct thread_data *td, const char *fname,
+				int need_swap)
 {
 	return 1;
 }
-- 
2.25.1