Add support for redirection replay of blktrace traces to another device
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/HOWTO b/HOWTO
index 2bbaad0..452e288 100644
--- a/HOWTO
+++ b/HOWTO
@@ -994,6 +994,23 @@
as possible while still respecting ordering. The result is the same
I/O pattern to a given device, but different timings.
+replay_redirect=str While replaying I/O patterns using read_iolog the
+ default behavior is to replay the IOPS onto the major/minor
+ device that each IOP was recorded from. This is sometimes
+ undesireable because on a different machine those major/minor
+ numbers can map to a different device. Changing hardware on
+ the same system can also result in a different major/minor
+ mapping. Replay_redirect causes all IOPS to be replayed onto
+ the single specified device regardless of the device it was
+ recorded from. i.e. replay_redirect=/dev/sdc would cause all
+ IO in the blktrace to be replayed onto /dev/sdc. This means
+ multiple devices will be replayed onto a single, if the trace
+ contains multiple devices. If you want multiple devices to be
+ replayed concurrently to multiple redirected devices you must
+ blkparse your trace into separate traces and replay them with
+ independent fio invocations. Unfortuantely this also breaks
+ the strict time ordering between multiple device accesses.
+
write_bw_log=str If given, write a bandwidth log of the jobs in this job
file. Can be used to store data of the bandwidth of the
jobs in their lifetime. The included fio_generate_plots
diff --git a/blktrace.c b/blktrace.c
index f22ab1b..9ce4ae2 100644
--- a/blktrace.c
+++ b/blktrace.c
@@ -97,7 +97,8 @@
return 0;
}
-static int lookup_device(char *path, unsigned int maj, unsigned int min)
+static int lookup_device(struct thread_data *td, char *path, unsigned int maj,
+ unsigned int min)
{
struct dirent *dir;
struct stat st;
@@ -121,7 +122,7 @@
}
if (S_ISDIR(st.st_mode)) {
- found = lookup_device(full_path, maj, min);
+ found = lookup_device(td, full_path, maj, min);
if (found) {
strcpy(path, full_path);
break;
@@ -131,6 +132,20 @@
if (!S_ISBLK(st.st_mode))
continue;
+ /*
+ * If replay_redirect is set then always return this device
+ * upon lookup which overrides the device lookup based on
+ * major minor in the actual blktrace
+ */
+ if (td->o.replay_redirect) {
+ dprint(FD_BLKTRACE, "device lookup: %d/%d\n overridden"
+ " with: %s", maj, min,
+ td->o.replay_redirect);
+ strcpy(path, td->o.replay_redirect);
+ found = 1;
+ break;
+ }
+
if (maj == major(st.st_rdev) && min == minor(st.st_rdev)) {
dprint(FD_BLKTRACE, "device lookup: %d/%d\n", maj, min);
strcpy(path, full_path);
@@ -183,7 +198,7 @@
return;
strcpy(dev, "/dev");
- if (lookup_device(dev, maj, min)) {
+ if (lookup_device(td, dev, maj, min)) {
int fileno;
dprint(FD_BLKTRACE, "add devices %s\n", dev);
diff --git a/fio.1 b/fio.1
index 1c0dc79..192e6a8 100644
--- a/fio.1
+++ b/fio.1
@@ -746,6 +746,12 @@
\fBreplay_no_stall\fR causes I/Os to be replayed as fast as possible while
still respecting ordering.
.TP
+.BI replay_redirect \fR=\fPstr
+While replaying I/O patterns using \fBread_iolog\fR the default behavior
+is to replay the IOPS onto the major/minor device that each IOP was recorded
+from. Setting \fBreplay_redirect\fR causes all IOPS to be replayed onto the
+single specified device regardless of the device it was recorded from.
+.TP
.B write_bw_log \fR=\fPstr
If given, write a bandwidth log of the jobs in this job file. Can be used to
store data of the bandwidth of the jobs in their lifetime. The included
diff --git a/fio.h b/fio.h
index ad47762..729604d 100644
--- a/fio.h
+++ b/fio.h
@@ -260,6 +260,7 @@
char *write_iolog_file;
char *bw_log_file;
char *lat_log_file;
+ char *replay_redirect;
/*
* Pre-run and post-run shell
diff --git a/options.c b/options.c
index 9718dc5..3d32c8e 100644
--- a/options.c
+++ b/options.c
@@ -1490,6 +1490,13 @@
.help = "Playback IO pattern file as fast as possible without stalls",
},
{
+ .name = "replay_redirect",
+ .type = FIO_OPT_STR_STORE,
+ .off1 = td_var_offset(replay_redirect),
+ .parent = "read_iolog",
+ .help = "Replay all I/O onto this device, regardless of trace device",
+ },
+ {
.name = "exec_prerun",
.type = FIO_OPT_STR_STORE,
.off1 = td_var_offset(exec_prerun),