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Message-id: <016701ced4fc$bb7afe10$3270fa30$@samsung.com>
Date: Wed, 30 Oct 2013 08:15:18 +0900
From: Changman Lee <cm224.lee@...sung.com>
To: 'Chao Yu' <chao2.yu@...sung.com>, jaegeuk.kim@...sung.com
Cc: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net
Subject: RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap
with bitops for better mount performance
Firstly,
Thanks. You're right. And I don't know it would be optimized but considering
pipeline.
for ( i =0; i < SIT_VBLOCK_MAP_SIZE; i += 4) {
valid_blocks += bit_count_byte(raw_sit->valid_map[i];
valid_blocks += bit_count_byte(raw_sit->valid_map[i+1];
valid_blocks += bit_count_byte(raw_sit->valid_map[i+2];
valid_blocks += bit_count_byte(raw_sit->valid_map[i+3];
}
Secondly,
I think also your patch is good in lots of case NOT aging for long time.
-----Original Message-----
From: Chao Yu [mailto:chao2.yu@...sung.com]
Sent: Tuesday, October 29, 2013 7:07 PM
To: 'Changman Lee'; jaegeuk.kim@...sung.com
Cc: linux-fsdevel@...r.kernel.org; linux-kernel@...r.kernel.org;
linux-f2fs-devel@...ts.sourceforge.net
Subject: RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros
bitmap with bitops for better mount performance
Hi Lee,
It's a good point.
Firstly, In your patch:
/* check bitmap with valid block count */
for (i = 0; i < sbi->blocks_per_seg; i++)
- if (f2fs_test_bit(i, raw_sit->valid_map))
- valid_blocks++;
+ valid_blocks += bit_count_byte(raw_sit->valid_map[i]);
+
BUG_ON(GET_SIT_VBLOCKS(raw_sit) != valid_blocks); }
for (i = 0; i < sbi->blocks_per_seg; i++) should be replace with for (i = 0;
i < SIT_VBLOCK_MAP_SIZE; i++)
Secondly, I tested your patch and mine
with SD and emmc with all zeros bitmap.
It shows my patch takes litter time.
Could you test and compare the performance of two patches.
--
1.7.10.4
> -----Original Message-----
> From: Changman Lee [mailto:cm224.lee@...sung.com]
> Sent: Tuesday, October 29, 2013 3:36 PM
> To: 'Chao Yu'; jaegeuk.kim@...sung.com
> Cc: linux-fsdevel@...r.kernel.org; linux-kernel@...r.kernel.org;
> linux-f2fs-devel@...ts.sourceforge.net
> Subject: RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros
bitmap
> with bitops for better mount performance
>
> Review attached patch, please.
>
> -----Original Message-----
> From: Chao Yu [mailto:chao2.yu@...sung.com]
> Sent: Tuesday, October 29, 2013 3:51 PM
> To: jaegeuk.kim@...sung.com
> Cc: linux-fsdevel@...r.kernel.org; linux-kernel@...r.kernel.org;
> linux-f2fs-devel@...ts.sourceforge.net
> Subject: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap
with
> bitops for better mount performance
>
> Previously, check_block_count check valid_map with bit data type in common
> scenario that sit has all ones or zeros bitmap, it makes low mount
> performance.
> So let's check the special bitmap with integer data type instead of the
bit one.
>
> v1-->v2:
> use find_next_{zero_}bit_le for better performance and readable as
> Jaegeuk suggested.
> use neat logogram in comment as Gu Zheng suggested.
> search continuous ones or zeros for better performance when checking
> mixed bitmap.
>
> Suggested-by: Jaegeuk Kim <jaegeuk.kim@...sung.com>
> Signed-off-by: Shu Tan <shu.tan@...sung.com>
> Signed-off-by: Chao Yu <chao2.yu@...sung.com>
> ---
> fs/f2fs/segment.h | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index abe7094..a7abfa8
> 100644
> --- a/fs/f2fs/segment.h
> +++ b/fs/f2fs/segment.h
> @@ -550,8 +550,9 @@ static inline void check_block_count(struct
> f2fs_sb_info *sbi, {
> struct f2fs_sm_info *sm_info = SM_I(sbi);
> unsigned int end_segno = sm_info->segment_count - 1;
> + bool is_valid = test_bit_le(0, raw_sit->valid_map) ? true : false;
> int valid_blocks = 0;
> - int i;
> + int cur_pos = 0, next_pos;
>
> /* check segment usage */
> BUG_ON(GET_SIT_VBLOCKS(raw_sit) > sbi->blocks_per_seg); @@ -560,9
> +561,19 @@ static inline void check_block_count(struct f2fs_sb_info
> +*sbi,
> BUG_ON(segno > end_segno);
>
> /* check bitmap with valid block count */
> - for (i = 0; i < sbi->blocks_per_seg; i++)
> - if (f2fs_test_bit(i, raw_sit->valid_map))
> - valid_blocks++;
> + do {
> + if (is_valid) {
> + next_pos =
> find_next_zero_bit_le(&raw_sit->valid_map,
> + sbi->blocks_per_seg,
> + cur_pos);
> + valid_blocks += next_pos - cur_pos;
> + } else
> + next_pos = find_next_bit_le(&raw_sit->valid_map,
> + sbi->blocks_per_seg,
> + cur_pos);
> + cur_pos = next_pos;
> + is_valid = !is_valid;
> + } while (cur_pos < sbi->blocks_per_seg);
> BUG_ON(GET_SIT_VBLOCKS(raw_sit) != valid_blocks); }
>
> --
> 1.7.9.5
>
>
>
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> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@...ts.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
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