>I'd stop referencing blockalign here to avoid confusion
Done.
>Actually it will should apply to all workloads because a random workload won't be able to generate an offset that is less than the aligned offset.
The offset_align will only apply if % is used in offset (not byte offset). Agreed if sequential or random IO, get_start_offset() is invoked for starting LBA. Applied updates.
>Why check ba here? I don't think we get anything from trying to align the offset to blockalign given its behaviour.
Done.
>Isn't FIO_OPT_INT more appropriate?
Good point, same as blockalign.
>Actually here's a question - what does .interval do?
Looks like it is used to override the default value of 1 in gopt_new_int():
interval = 1.0;
if (o->interval)
interval = o->interval;
i->spin = gtk_spin_button_new_with_range(o->minval, maxval, interval);
But your larger question may be why do some options have interval (e.g. offset) and some not have interval (e.g. ioengine).
Here is a v2 patch:
diff --git a/HOWTO b/HOWTO
index 22a5849..e7142c5 100644
--- a/HOWTO
+++ b/HOWTO
@@ -1128,13 +1128,20 @@ I/O type
.. option:: offset=int
Start I/O at the provided offset in the file, given as either a fixed size in
- bytes or a percentage. If a percentage is given, the next ``blockalign``-ed
- offset will be used. Data before the given offset will not be touched. This
+ bytes or a percentage. If a percentage is given, the generated offset will be
+ aligned to the minimum ``blocksize`` or to the value of ``offset_align`` if
+ provided. Data before the given offset will not be touched. This
effectively caps the file size at `real_size - offset`. Can be combined with
:option:`size` to constrain the start and end range of the I/O workload.
A percentage can be specified by a number between 1 and 100 followed by '%',
for example, ``offset=20%`` to specify 20%.
+.. option:: offset_align=int
+
+ If set to non-zero value, the byte offset generated by a percentage ``offset``
+ is aligned upwards to this value. Defaults to 0 meaning that a percentage
+ offset is aligned to the minimum block size.
+
.. option:: offset_increment=int
If this is provided, then the real offset becomes `offset + offset_increment
diff --git a/cconv.c b/cconv.c
index f809fd5..dc3c4e6 100644
--- a/cconv.c
+++ b/cconv.c
@@ -105,6 +105,7 @@ void convert_thread_options_to_cpu(struct thread_options *o,
o->file_size_low = le64_to_cpu(top->file_size_low);
o->file_size_high = le64_to_cpu(top->file_size_high);
o->start_offset = le64_to_cpu(top->start_offset);
+ o->start_offset_align = le64_to_cpu(top->start_offset_align);
o->start_offset_percent = le32_to_cpu(top->start_offset_percent);
for (i = 0; i < DDIR_RWDIR_CNT; i++) {
@@ -548,6 +549,7 @@ void convert_thread_options_to_net(struct thread_options_pack *top,
top->file_size_low = __cpu_to_le64(o->file_size_low);
top->file_size_high = __cpu_to_le64(o->file_size_high);
top->start_offset = __cpu_to_le64(o->start_offset);
+ top->start_offset_align = __cpu_to_le64(o->start_offset_align);
top->start_offset_percent = __cpu_to_le32(o->start_offset_percent);
top->trim_backlog = __cpu_to_le64(o->trim_backlog);
top->offset_increment = __cpu_to_le64(o->offset_increment);
diff --git a/filesetup.c b/filesetup.c
index 7a602d4..5d7ea5c 100644
--- a/filesetup.c
+++ b/filesetup.c
@@ -869,12 +869,10 @@ uint64_t get_start_offset(struct thread_data *td, struct fio_file *f)
if (o->start_offset_percent > 0) {
/*
- * if blockalign is provided, find the min across read, write,
- * and trim
+ * if offset_align is provided, set initial offset
*/
- if (fio_option_is_set(o, ba)) {
- align_bs = (unsigned long long) min(o->ba[DDIR_READ], o->ba[DDIR_WRITE]);
- align_bs = min((unsigned long long) o->ba[DDIR_TRIM], align_bs);
+ if (fio_option_is_set(o, start_offset_align)) {
+ align_bs = o->start_offset_align;
} else {
/* else take the minimum block size */
align_bs = td_min_bs(td);
diff --git a/fio.1 b/fio.1
index 7787ef2..96d8f11 100644
--- a/fio.1
+++ b/fio.1
@@ -913,13 +913,19 @@ should be associated with them.
.TP
.BI offset \fR=\fPint
Start I/O at the provided offset in the file, given as either a fixed size in
-bytes or a percentage. If a percentage is given, the next \fBblockalign\fR\-ed
-offset will be used. Data before the given offset will not be touched. This
+bytes or a percentage. If a percentage is given, the generated offset will be
+aligned to the minimum \fBblocksize\fR or to the value of \fBoffset_align\fR if
+provided. Data before the given offset will not be touched. This
effectively caps the file size at `real_size \- offset'. Can be combined with
\fBsize\fR to constrain the start and end range of the I/O workload.
A percentage can be specified by a number between 1 and 100 followed by '%',
for example, `offset=20%' to specify 20%.
.TP
+.BI offset_align \fR=\fPint
+If set to non-zero value, the byte offset generated by a percentage \fBoffset\fR
+is aligned upwards to this value. Defaults to 0 meaning that a percentage
+offset is aligned to the minimum block size.
+.TP
.BI offset_increment \fR=\fPint
If this is provided, then the real offset becomes `\fBoffset\fR + \fBoffset_increment\fR
* thread_number', where the thread number is a counter that starts at 0 and
diff --git a/options.c b/options.c
index ddcc4e5..e88dc2c 100644
--- a/options.c
+++ b/options.c
@@ -2019,6 +2019,17 @@ struct fio_option fio_options[FIO_MAX_OPTS] = {
.group = FIO_OPT_G_INVALID,
},
{
+ .name = "offset_align",
+ .lname = "IO offset alignment",
+ .type = FIO_OPT_INT,
+ .off1 = offsetof(struct thread_options, start_offset_align),
+ .help = "Start IO from this offset alignment",
+ .def = "0",
+ .interval = 1024 * 1024,
+ .category = FIO_OPT_C_IO,
+ .group = FIO_OPT_G_INVALID,
+ },
+ {
.name = "offset_increment",
.lname = "IO offset increment",
.type = FIO_OPT_STR_VAL,
diff --git a/thread_options.h b/thread_options.h
index 1813cdc..5a037bf 100644
--- a/thread_options.h
+++ b/thread_options.h
@@ -78,6 +78,7 @@ struct thread_options {
unsigned long long file_size_low;
unsigned long long file_size_high;
unsigned long long start_offset;
+ unsigned long long start_offset_align;
unsigned int bs[DDIR_RWDIR_CNT];
unsigned int ba[DDIR_RWDIR_CNT];
@@ -355,6 +356,7 @@ struct thread_options_pack {
uint64_t file_size_low;
uint64_t file_size_high;
uint64_t start_offset;
+ uint64_t start_offset_align;
uint32_t bs[DDIR_RWDIR_CNT];
uint32_t ba[DDIR_RWDIR_CNT];
Regards,
Jeff
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