IOshark portability across 32- and 64-bit, little/big endian devices.

Make IOshark portable across 32-bit and 64-bit devices, as well as
little endian and big endian architectures. This is achieved by
locking down the on-disk format of IOshark workload files. We can now
generate the workload files on a 64-bit host and use those workload
files to run the benchmark on a 32-bit userspace device (such as
fugu). The change also has minor fixes to make IOshark work on taimen
and walleye.

Test: Test across 64- and 32-bit devices. Generate workload files on a
64 bit device and test on 32-bit devices (as well as 64-bit devices).

Change-Id: I700ca5ae0da0ab029d977c906a63f1cd20a78a14
Signed-off-by: Mohan Srinivasan <srmohan@google.com>

1 files changed, 72 insertions, 0 deletions

diff --git a/ioshark/README b/ioshark/README
index f71a2600..9a8eddc5 100644
--- a/ioshark/README
+++ b/ioshark/README
@@ -30,3 +30,75 @@ will launch as many threads as there are input files, so 1 thread/file.
 -s : One line summary.
 -q : Don't create the files in read-only partitions like /system and
 /vendor. Instead do reads on those files.
+
+FILE FORMAT :
+-----------
+
+Each IOshark workload file is composed of the following
+
+Header
+File State : Table of File Entries. Each entry describes a file
+File Op : Table of File Operations. One entry describes one operation
+
+Each of the above is described below :
+
+Note : Everything is in Big Endian byte order.
+
+Header {
+       /* IOshark version number */
+       u_int64_t	ioshark_version;
+       /* Total number of files used in this IOshark workload file */
+       u_int64_t	num_files;
+       /* Total number of IO operations in this IOshark workload file */
+       u_int64_t       num_io_operations;
+}
+
+File State {
+       u_int64_t	fileno;
+       u_int64_t	size;
+       u_int64_t 	global_filename_ix;
+}
+
+File Op {
+	/* delta us between previous file op and this */
+	u_int64_t		delta_us;
+#define file_op			file_op_union.file_op_u
+	union {
+		enum file_op		file_op_u;
+		int32_t			enum_size;
+	} file_op_union;
+	u_int64_t		fileno;
+	union {
+		struct lseek_args {
+#define lseek_offset	u.lseek_a.offset
+#define lseek_action	u.lseek_a.action
+			u_int64_t	offset;
+			int32_t		action;
+		} lseek_a;
+		struct prw_args {
+#define prw_offset	u.prw_a.offset
+#define prw_len		u.prw_a.len
+			u_int64_t	offset;
+			u_int64_t	len;
+		} prw_a;
+#define rw_len		u.rw_a.len
+		struct rw_args {
+			u_int64_t	len;
+		} rw_a;
+#define mmap_offset	u.mmap_a.offset
+#define mmap_len	u.mmap_a.len
+#define mmap_prot	u.mmap_a.prot
+		struct mmap_args {
+			u_int64_t	offset;
+			u_int64_t	len;
+			int32_t		prot;
+	} mmap_a;
+#define open_flags	u.open_a.flags
+#define open_mode	u.open_a.mode
+		struct open_args {
+			int32_t		flags;
+			int32_t		mode;
+		} open_a;
+	} u;
+
+}