* [PATCH 0/2] ZBD fix with random zone index logic and missing documentation.
[not found] <CGME20210803111208epcas5p2fec4fec945de52fb57986f2ef5e2bcfe@epcas5p2.samsung.com>
@ 2021-08-03 10:28 ` Ankit Kumar
[not found] ` <CGME20210803111237epcas5p3793e7b1dbb19ccad4841e5ba69ee1bb8@epcas5p3.samsung.com>
[not found] ` <CGME20210803111246epcas5p196f2a90009a00f639bbe5054570ac5a2@epcas5p1.samsung.com>
0 siblings, 2 replies; 5+ messages in thread
From: Ankit Kumar @ 2021-08-03 10:28 UTC (permalink / raw)
To: axboe; +Cc: fio, krish.reddy, prakash.v, Ankit Kumar
ZBD fix with random zone index logic and missing documentation.
Ankit Kumar (2):
Add missing documentation for job_max_open_zones.
zbd: Improve random zone index generation logic.
HOWTO | 5 +++++
zbd.c | 5 +++--
2 files changed, 8 insertions(+), 2 deletions(-)
--
1.8.3.1
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 1/2] Add missing documentation for job_max_open_zones.
[not found] ` <CGME20210803111237epcas5p3793e7b1dbb19ccad4841e5ba69ee1bb8@epcas5p3.samsung.com>
@ 2021-08-03 10:28 ` Ankit Kumar
2021-08-04 5:52 ` Shinichiro Kawasaki
0 siblings, 1 reply; 5+ messages in thread
From: Ankit Kumar @ 2021-08-03 10:28 UTC (permalink / raw)
To: axboe; +Cc: fio, krish.reddy, prakash.v, Ankit Kumar
---
HOWTO | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/HOWTO b/HOWTO
index 59c7f1f..d4e620d 100644
--- a/HOWTO
+++ b/HOWTO
@@ -1055,6 +1055,11 @@ Target file/device
number of open zones is defined as the number of zones to which write
commands are issued.
+.. option:: job_max_open_zones=int
+
+ Limit on the number of simultaneously opened zones per single
+ thread/process.
+
.. option:: zone_reset_threshold=float
A number between zero and one that indicates the ratio of logical
--
1.8.3.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH 2/2] zbd: Improve random zone index generation logic.
[not found] ` <CGME20210803111246epcas5p196f2a90009a00f639bbe5054570ac5a2@epcas5p1.samsung.com>
@ 2021-08-03 10:28 ` Ankit Kumar
2021-08-04 5:59 ` Shinichiro Kawasaki
0 siblings, 1 reply; 5+ messages in thread
From: Ankit Kumar @ 2021-08-03 10:28 UTC (permalink / raw)
To: axboe; +Cc: fio, krish.reddy, prakash.v, Ankit Kumar
Existing random zone index generation logic is dependent on the file size.
For smaller I/O sizes the random zone index always return a particular
section of open zones. As this index is used to return one of the open zones,
it was observed that after one of the max_open_zones / job_max_open_zones limit
is reached all further I/O's are redirected to only a few open zones till they
are full.
This patch modifies the random zone index genration logic so that it is uniform
across all the open zones.
---
zbd.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/zbd.c b/zbd.c
index 04c68de..43f12b4 100644
--- a/zbd.c
+++ b/zbd.c
@@ -1184,11 +1184,12 @@ out:
return res;
}
-/* Anything goes as long as it is not a constant. */
+/* Return random zone index for one of the open zones. */
static uint32_t pick_random_zone_idx(const struct fio_file *f,
const struct io_u *io_u)
{
- return io_u->offset * f->zbd_info->num_open_zones / f->real_file_size;
+ return (io_u->offset - f->file_offset) * f->zbd_info->num_open_zones /
+ f->io_size;
}
/*
--
1.8.3.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH 1/2] Add missing documentation for job_max_open_zones.
2021-08-03 10:28 ` [PATCH 1/2] Add missing documentation for job_max_open_zones Ankit Kumar
@ 2021-08-04 5:52 ` Shinichiro Kawasaki
0 siblings, 0 replies; 5+ messages in thread
From: Shinichiro Kawasaki @ 2021-08-04 5:52 UTC (permalink / raw)
To: Ankit Kumar; +Cc: axboe, fio, krish.reddy, prakash.v
Hello Ankit,
On Aug 03, 2021 / 15:58, Ankit Kumar wrote:
> ---
> HOWTO | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/HOWTO b/HOWTO
> index 59c7f1f..d4e620d 100644
> --- a/HOWTO
> +++ b/HOWTO
> @@ -1055,6 +1055,11 @@ Target file/device
> number of open zones is defined as the number of zones to which write
> commands are issued.
>
> +.. option:: job_max_open_zones=int
> +
> + Limit on the number of simultaneously opened zones per single
> + thread/process.
> +
This change looks good to me, but I think the commit message title can be
improved. "HOWTO: " prefix will help to identify the change target file. Also,
I suggest to remove the period in the title. As far as I know, all fio commits
do not have period in their commit message titles.
> .. option:: zone_reset_threshold=float
>
> A number between zero and one that indicates the ratio of logical
> --
> 1.8.3.1
>
--
Best Regards,
Shin'ichiro Kawasaki
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 2/2] zbd: Improve random zone index generation logic.
2021-08-03 10:28 ` [PATCH 2/2] zbd: Improve random zone index generation logic Ankit Kumar
@ 2021-08-04 5:59 ` Shinichiro Kawasaki
0 siblings, 0 replies; 5+ messages in thread
From: Shinichiro Kawasaki @ 2021-08-04 5:59 UTC (permalink / raw)
To: Ankit Kumar; +Cc: axboe, fio, krish.reddy, prakash.v
On Aug 03, 2021 / 15:58, Ankit Kumar wrote:
> Existing random zone index generation logic is dependent on the file size.
> For smaller I/O sizes the random zone index always return a particular
> section of open zones. As this index is used to return one of the open zones,
> it was observed that after one of the max_open_zones / job_max_open_zones limit
> is reached all further I/O's are redirected to only a few open zones till they
> are full.
>
> This patch modifies the random zone index genration logic so that it is uniform
> across all the open zones.
> ---
> zbd.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/zbd.c b/zbd.c
> index 04c68de..43f12b4 100644
> --- a/zbd.c
> +++ b/zbd.c
> @@ -1184,11 +1184,12 @@ out:
> return res;
> }
>
> -/* Anything goes as long as it is not a constant. */
> +/* Return random zone index for one of the open zones. */
> static uint32_t pick_random_zone_idx(const struct fio_file *f,
> const struct io_u *io_u)
> {
> - return io_u->offset * f->zbd_info->num_open_zones / f->real_file_size;
> + return (io_u->offset - f->file_offset) * f->zbd_info->num_open_zones /
> + f->io_size;
> }
One nit I suggest is to remove the period in the commit message title. Other
than that, I confirmed the change is good. I confirmed that it improves the
randomness of the open zone choice. It reverts the part of the commit 6463db6c1
('fio: fix interaction between offset/size limited threads and
"max_open_zones"'), but I confirmed that still the intent of the commit
6463db6c1 is kept after applying this change.
Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
--
Best Regards,
Shin'ichiro Kawasaki
^ permalink raw reply [flat|nested] 5+ messages in thread
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2021-08-03 10:28 ` [PATCH 0/2] ZBD fix with random zone index logic and missing documentation Ankit Kumar
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2021-08-04 5:52 ` Shinichiro Kawasaki
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2021-08-03 10:28 ` [PATCH 2/2] zbd: Improve random zone index generation logic Ankit Kumar
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