On 24 October 2017 at 00:56, Jeff Furlong <jeff.furlong@xxxxxxx> wrote:
>
> diff --git a/HOWTO b/HOWTO
> index 22a5849..c611fae 100644
> --- a/HOWTO
> +++ b/HOWTO
> @@ -1128,13 +1128,19 @@ 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
> + bytes or a percentage. If a percentage is given, the next ``bs`` ``blockalign``-ed
I'd stop referencing blockalign here to avoid confusion and say something like:
When a percentage is given, the generated offset will be aligned up to
the minimum ``blocksize`` or to the value of ``offset_align``.
> offset will be used. 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 a precentage offset is given, the provided offset is ``blockalign``-ed to
> + the ``blocksize``. This value will align the initial I/O to a new alignment
> + Applies to sequential workloads only.
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. I'd go with something like the following:
If set to a non-zero number, the value 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.
> --- a/filesetup.c
> +++ b/filesetup.c
> @@ -869,10 +869,15 @@ uint64_t get_start_offset(struct thread_data *td, struct fio_file *f)
>
> if (o->start_offset_percent > 0) {
> /*
> + * if offset_align is provided, set initial offset
> + */
> + if (fio_option_is_set(o, start_offset_align)) {
> + align_bs = o->start_offset_align;
> + /*
> * if blockalign is provided, find the min across read, write,
> * and trim
> */
> - if (fio_option_is_set(o, ba)) {
> + } else 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);
Why check ba here? I don't think we get anything from trying to align
the offset to blockalign given its behaviour.
> } else {
> diff --git a/fio.1 b/fio.1
> index 7787ef2..098ca2e 100644
> --- a/fio.1
> +++ b/fio.1
> @@ -913,13 +913,18 @@ 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
> +bytes or a percentage. If a percentage is given, the next \fBbs\fR \fBblockalign\fR\-ed
> offset will be used. 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%.
See above for documentation suggestions.
> .TP
> +.BI offset_align \fR=\fPint
> +If a precentage offset is given, the provided offset is \fBblockalign\fR\-ed to
> +the \fBblocksize\fR. This value will align the initial I/O to a new alignment.
> +Applies to sequential workloads only.
> +.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..a7821d7 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_STR_VAL,
Isn't FIO_OPT_INT more appropriate?
> + .off1 = offsetof(struct thread_options, start_offset_align),
> + .help = "Start IO from this offset alignment",
> + .def = "0",
> + .interval = 1024 * 1024,
Actually here's a question - what does .interval do?
> + .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
Thanks for trying this out Jeff!
--
Sitsofe | http://sucs.org/~sits/
--
To unsubscribe from this list: send the line "unsubscribe fio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
