On Fri, Sep 25, 2015 at 07:42:25AM +0200, Marc Lehmann wrote:
> On Thu, Sep 24, 2015 at 10:27:49AM -0700, Jaegeuk Kim <jaeg...@kernel.org>
> wrote:
> > > In the end, I might settle with -s64, and currently do tests with -s90.
> >
> > Got it. But why -s90? :)
>
> He :) It's a nothing-special number between 64 and 128, that's all.
Oh, then, I don't think that is a good magic number.
It seems that you decided to use -s64, so it'd better to keep it to address
any perf results.
> > I just pushed the patches to master branch in f2fs-tools.git.
> > Could you pull them and check them?
>
> Got them, last patch was the "check sit types" change.
>
> > I added one more patch to avoid harmless sit_type fixes previously you
> > reported.
> >
> > And, for the 8TB case, let me check again. It seems that we need to handle
> > under
> > 1% overprovision ratio. (e.g., 0.5%)
>
> That might make me potentially very happy. But my main concern at the
> moment is stability - even when you have a backup, restoring 8TB will take
> days, and backups are never uptodate.
>
> It would be nice to be able to control it more from the user side though.
>
> For example, I have not yet reached 0.0% free with f2fs. That's fine, I don't
> plan9 to, but I need to know at which percentage should I stop, which is
> something I can only really find out with experiments.
>
> And just filling these 8TB disks takes days, so the question is, can I
> simulate near-full behaviour with smaller partitions.
Why not? :)
I think the behavior should be same. And, it'd good to set small sections
in order to see it more clearly.
Anyway, I wrote a patch to consider under 1% for large partitions.
section ovp ratio ovp size
For 8TB,
-s1 : 0.07% -> 10GB
-s32 : 0.39% -> 65GB
-s64 : 0.55% -> 92GB
-s128 : 0.78% -> 132GB
For 128GB,
-s1 : 0.55% -> 1.4GB
-s32 : 3.14% -> 8GB
-s64 : 4.45% -> 12GB
-s128 : 6.32% -> 17GB
Let me test this patch for a while, and then push into our git.
Thanks,
>From 2cdb04b52f202e931e370564396366d44bd4d1e2 Mon Sep 17 00:00:00 2001
From: Jaegeuk Kim <jaeg...@kernel.org>
Date: Fri, 25 Sep 2015 09:31:04 -0700
Subject: [PATCH] mkfs.f2fs: support <1% overprovision ratio
Big partition size needs uner 1% overprovision space to acquire more space.
section ovp ratio ovp size
For 8TB,
-s1 : 0.07% -> 10GB
-s32 : 0.39% -> 65GB
-s64 : 0.55% -> 92GB
-s128 : 0.78% -> 132GB
For 128GB,
-s1 : 0.55% -> 1.4GB
-s32 : 3.14% -> 8GB
-s64 : 4.45% -> 12GB
-s128 : 6.32% -> 17GB
Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org>
---
include/f2fs_fs.h | 2 +-
mkfs/f2fs_format.c | 12 ++++++------
mkfs/f2fs_format_main.c | 2 +-
3 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/include/f2fs_fs.h b/include/f2fs_fs.h
index 38a774c..359deec 100644
--- a/include/f2fs_fs.h
+++ b/include/f2fs_fs.h
@@ -225,7 +225,7 @@ enum f2fs_config_func {
struct f2fs_configuration {
u_int32_t sector_size;
u_int32_t reserved_segments;
- u_int32_t overprovision;
+ double overprovision;
u_int32_t cur_seg[6];
u_int32_t segs_per_sec;
u_int32_t secs_per_zone;
diff --git a/mkfs/f2fs_format.c b/mkfs/f2fs_format.c
index 2d4ab09..176bdea 100644
--- a/mkfs/f2fs_format.c
+++ b/mkfs/f2fs_format.c
@@ -155,19 +155,19 @@ static void configure_extension_list(void)
free(config.extension_list);
}
-static u_int32_t get_best_overprovision(void)
+static double get_best_overprovision(void)
{
- u_int32_t reserved, ovp, candidate, end, diff, space;
- u_int32_t max_ovp = 0, max_space = 0;
+ double reserved, ovp, candidate, end, diff, space;
+ double max_ovp = 0, max_space = 0;
if (get_sb(segment_count_main) < 256) {
candidate = 10;
end = 95;
diff = 5;
} else {
- candidate = 1;
+ candidate = 0.01;
end = 10;
- diff = 1;
+ diff = 0.01;
}
for (; candidate <= end; candidate += diff) {
@@ -533,7 +533,7 @@ static int f2fs_write_check_point_pack(void)
set_cp(overprov_segment_count, get_cp(overprov_segment_count) +
get_cp(rsvd_segment_count));
- MSG(0, "Info: Overprovision ratio = %u%%\n", config.overprovision);
+ MSG(0, "Info: Overprovision ratio = %.3lf%%\n", config.overprovision);
MSG(0, "Info: Overprovision segments = %u (GC reserved = %u)\n",
get_cp(overprov_segment_count),
config.reserved_segments);
diff --git a/mkfs/f2fs_format_main.c b/mkfs/f2fs_format_main.c
index fc612d8..2ea809c 100644
--- a/mkfs/f2fs_format_main.c
+++ b/mkfs/f2fs_format_main.c
@@ -99,7 +99,7 @@ static void f2fs_parse_options(int argc, char *argv[])
config.vol_label = optarg;
break;
case 'o':
- config.overprovision = atoi(optarg);
+ config.overprovision = atof(optarg);
break;
case 'O':
parse_feature(strdup(optarg));
--
2.1.1
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