2013-10-24 08:22:35

by Chao Yu

[permalink] [raw]
Subject: [f2fs-dev] [PATCH V2] 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.

v2:
use find_next_bit_le/find_next_zero_bit_le for better performance and readable as Jaegeuk suggested.

Suggested-by: Jaegeuk Kim <[email protected]>
Signed-off-by: Tan Shu <[email protected]>
Signed-off-by: Yu Chao <[email protected]>
---
fs/f2fs/segment.h | 17 +++++++++++++++++
1 file changed, 17 insertions(+)

diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 7f94d78..d25b6af 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -552,6 +552,23 @@ static inline void check_block_count(struct f2fs_sb_info *sbi,
/* check boundary of a given segment number */
BUG_ON(segno > end_segno);

+ /* check all ones or zeros valid_map */
+ if (GET_SIT_VBLOCKS(raw_sit) == 0) {
+ int pos = find_next_bit_le(&raw_sit->valid_map,
+ sbi->blocks_per_seg,
+ 0);
+ if (pos != sbi->blocks_per_seg)
+ BUG();
+ return;
+ } else if (GET_SIT_VBLOCKS(raw_sit) == sbi->blocks_per_seg) {
+ int pos = find_next_zero_bit_le(&raw_sit->valid_map,
+ sbi->blocks_per_seg,
+ 0);
+ if (pos != sbi->blocks_per_seg)
+ BUG();
+ return;
+ }
+
/* check bitmap with valid block count */
for (i = 0; i < sbi->blocks_per_seg; i++)
if (f2fs_test_bit(i, raw_sit->valid_map))
--
1.7.9.5


2013-10-24 10:09:25

by Gu Zheng

[permalink] [raw]
Subject: Re: [f2fs-dev] [PATCH V2] f2fs: check all ones or zeros bitmap with bitops for better mount performance

Hi Yu,
On 10/24/2013 04:21 PM, Chao Yu wrote:

> 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.
>
> v2:
> use find_next_bit_le/find_next_zero_bit_le for better performance and readable as Jaegeuk suggested.

If so, how about using find_first_{zero_}bit_le instead? It's more neat.

Regards,
Gu

>
> Suggested-by: Jaegeuk Kim <[email protected]>
> Signed-off-by: Tan Shu <[email protected]>
> Signed-off-by: Yu Chao <[email protected]>
> ---
> fs/f2fs/segment.h | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
> index 7f94d78..d25b6af 100644
> --- a/fs/f2fs/segment.h
> +++ b/fs/f2fs/segment.h
> @@ -552,6 +552,23 @@ static inline void check_block_count(struct f2fs_sb_info *sbi,
> /* check boundary of a given segment number */
> BUG_ON(segno > end_segno);
>
> + /* check all ones or zeros valid_map */
> + if (GET_SIT_VBLOCKS(raw_sit) == 0) {
> + int pos = find_next_bit_le(&raw_sit->valid_map,
> + sbi->blocks_per_seg,
> + 0);
> + if (pos != sbi->blocks_per_seg)
> + BUG();
> + return;
> + } else if (GET_SIT_VBLOCKS(raw_sit) == sbi->blocks_per_seg) {
> + int pos = find_next_zero_bit_le(&raw_sit->valid_map,
> + sbi->blocks_per_seg,
> + 0);
> + if (pos != sbi->blocks_per_seg)
> + BUG();
> + return;
> + }
> +
> /* check bitmap with valid block count */
> for (i = 0; i < sbi->blocks_per_seg; i++)
> if (f2fs_test_bit(i, raw_sit->valid_map))

2013-10-25 01:35:50

by Chao Yu

[permalink] [raw]
Subject: RE: [f2fs-dev] [PATCH V2] f2fs: check all ones or zeros bitmap with bitops for better mount performance

Hi Gu,

> -----Original Message-----
> From: Gu Zheng [mailto:[email protected]]
> Sent: Thursday, October 24, 2013 6:04 PM
> To: Chao Yu
> Cc: [email protected]; [email protected];
> [email protected]; [email protected]; '谭姝'
> Subject: Re: [f2fs-dev] [PATCH V2] f2fs: check all ones or zeros bitmap with
> bitops for better mount performance
>
> Hi Yu,
> On 10/24/2013 04:21 PM, Chao Yu wrote:
>
> > 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.
> >
> > v2:
> > use find_next_bit_le/find_next_zero_bit_le for better performance and
> readable as Jaegeuk suggested.
>
> If so, how about using find_first_{zero_}bit_le instead? It's more neat.
It seems more neat. I will take it, thanks.

>
> Regards,
> Gu
>
> >
> > Suggested-by: Jaegeuk Kim <[email protected]>
> > Signed-off-by: Tan Shu <[email protected]>
> > Signed-off-by: Yu Chao <[email protected]>
> > ---
> > fs/f2fs/segment.h | 17 +++++++++++++++++
> > 1 file changed, 17 insertions(+)
> >
> > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index
> > 7f94d78..d25b6af 100644
> > --- a/fs/f2fs/segment.h
> > +++ b/fs/f2fs/segment.h
> > @@ -552,6 +552,23 @@ static inline void check_block_count(struct
> f2fs_sb_info *sbi,
> > /* check boundary of a given segment number */
> > BUG_ON(segno > end_segno);
> >
> > + /* check all ones or zeros valid_map */
> > + if (GET_SIT_VBLOCKS(raw_sit) == 0) {
> > + int pos = find_next_bit_le(&raw_sit->valid_map,
> > + sbi->blocks_per_seg,
> > + 0);
> > + if (pos != sbi->blocks_per_seg)
> > + BUG();
> > + return;
> > + } else if (GET_SIT_VBLOCKS(raw_sit) == sbi->blocks_per_seg) {
> > + int pos = find_next_zero_bit_le(&raw_sit->valid_map,
> > + sbi->blocks_per_seg,
> > + 0);
> > + if (pos != sbi->blocks_per_seg)
> > + BUG();
> > + return;
> > + }
> > +
> > /* check bitmap with valid block count */
> > for (i = 0; i < sbi->blocks_per_seg; i++)
> > if (f2fs_test_bit(i, raw_sit->valid_map))

2013-10-28 02:20:02

by Changman Lee

[permalink] [raw]
Subject: RE: [f2fs-dev] [PATCH V2] f2fs: check all ones or zeros bitmap with bitops for better mount performance

To check whether bitmap are all zeros or all ones, I think memcmp is more neat.
But I don't know exactly performance gap between memcmp and find_next_bit.


-----Original Message-----
From: Chao Yu [mailto:[email protected]]
Sent: Thursday, October 24, 2013 5:21 PM
To: [email protected]
Cc: [email protected]; '谭姝'; [email protected]; [email protected]
Subject: [f2fs-dev] [PATCH V2] 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.

v2:
use find_next_bit_le/find_next_zero_bit_le for better performance and readable as Jaegeuk suggested.

Suggested-by: Jaegeuk Kim <[email protected]>
Signed-off-by: Tan Shu <[email protected]>
Signed-off-by: Yu Chao <[email protected]>
---
fs/f2fs/segment.h | 17 +++++++++++++++++
1 file changed, 17 insertions(+)

diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index 7f94d78..d25b6af 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -552,6 +552,23 @@ static inline void check_block_count(struct f2fs_sb_info *sbi,
/* check boundary of a given segment number */
BUG_ON(segno > end_segno);

+ /* check all ones or zeros valid_map */
+ if (GET_SIT_VBLOCKS(raw_sit) == 0) {
+ int pos = find_next_bit_le(&raw_sit->valid_map,
+ sbi->blocks_per_seg,
+ 0);
+ if (pos != sbi->blocks_per_seg)
+ BUG();
+ return;
+ } else if (GET_SIT_VBLOCKS(raw_sit) == sbi->blocks_per_seg) {
+ int pos = find_next_zero_bit_le(&raw_sit->valid_map,
+ sbi->blocks_per_seg,
+ 0);
+ if (pos != sbi->blocks_per_seg)
+ BUG();
+ return;
+ }
+
/* check bitmap with valid block count */
for (i = 0; i < sbi->blocks_per_seg; i++)
if (f2fs_test_bit(i, raw_sit->valid_map))
--
1.7.9.5


------------------------------------------------------------------------------
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2013-10-28 02:37:02

by Gu Zheng

[permalink] [raw]
Subject: Re: [f2fs-dev] [PATCH V2] f2fs: check all ones or zeros bitmap with bitops for better mount performance

On 10/28/2013 10:19 AM, 이창만 wrote:

> To check whether bitmap are all zeros or all ones, I think memcmp is more neat.
> But I don't know exactly performance gap between memcmp and find_next_bit.

According to my understanding,
memcmp: one by one search,
find_next_bit: binary search.

Regards,
Gu

>
>
> -----Original Message-----
> From: Chao Yu [mailto:[email protected]]
> Sent: Thursday, October 24, 2013 5:21 PM
> To: [email protected]
> Cc: [email protected]; '谭姝'; [email protected]; [email protected]
> Subject: [f2fs-dev] [PATCH V2] 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.
>
> v2:
> use find_next_bit_le/find_next_zero_bit_le for better performance and readable as Jaegeuk suggested.
>
> Suggested-by: Jaegeuk Kim <[email protected]>
> Signed-off-by: Tan Shu <[email protected]>
> Signed-off-by: Yu Chao <[email protected]>
> ---
> fs/f2fs/segment.h | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index 7f94d78..d25b6af 100644
> --- a/fs/f2fs/segment.h
> +++ b/fs/f2fs/segment.h
> @@ -552,6 +552,23 @@ static inline void check_block_count(struct f2fs_sb_info *sbi,
> /* check boundary of a given segment number */
> BUG_ON(segno > end_segno);
>
> + /* check all ones or zeros valid_map */
> + if (GET_SIT_VBLOCKS(raw_sit) == 0) {
> + int pos = find_next_bit_le(&raw_sit->valid_map,
> + sbi->blocks_per_seg,
> + 0);
> + if (pos != sbi->blocks_per_seg)
> + BUG();
> + return;
> + } else if (GET_SIT_VBLOCKS(raw_sit) == sbi->blocks_per_seg) {
> + int pos = find_next_zero_bit_le(&raw_sit->valid_map,
> + sbi->blocks_per_seg,
> + 0);
> + if (pos != sbi->blocks_per_seg)
> + BUG();
> + return;
> + }
> +
> /* check bitmap with valid block count */
> for (i = 0; i < sbi->blocks_per_seg; i++)
> if (f2fs_test_bit(i, raw_sit->valid_map))
> --
> 1.7.9.5
>
>
> ------------------------------------------------------------------------------
> October Webinars: Code for Performance
> Free Intel webinars can help you accelerate application performance.
> Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from
> the latest Intel processors and coprocessors. See abstracts and register >
> http://pubads.g.doubleclick.net/gampad/clk?id=60135991&iu=/4140/ostg.clktrk
> _______________________________________________
> Linux-f2fs-devel mailing list
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> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
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>

2013-10-28 07:08:27

by Chao Yu

[permalink] [raw]
Subject: RE: [f2fs-dev] [PATCH V2] f2fs: check all ones or zeros bitmap with bitops for better mount performance

Hi Lee,

> -----Original Message-----
> From: 이창만 [mailto:[email protected]]
> Sent: Monday, October 28, 2013 10:20 AM
> To: 'Chao Yu'; [email protected]
> Cc: [email protected]; '谭姝'; [email protected];
> [email protected]
> Subject: RE: [f2fs-dev] [PATCH V2] f2fs: check all ones or zeros bitmap with
> bitops for better mount performance
>
> To check whether bitmap are all zeros or all ones, I think memcmp is more
> neat.
> But I don't know exactly performance gap between memcmp and
> find_next_bit.

With the result of my test, find_next_bit takes less time than memcmp.
If we could use {test, set, clear}_bit_le intead of f2fs_{test, set, clear}_bit, the following patch
could be used for better performance.
This one is better than the V2 patch for performance with mixed bitmap in my test.

diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 7f94d78..32153eb
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -544,7 +544,8 @@ 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;
int valid_blocks = 0;
- int i;
+ int i, cur_pos = 0, next_pos;
+ bool is_valid;

/* check segment usage */
BUG_ON(GET_SIT_VBLOCKS(raw_sit) > sbi->blocks_per_seg);
@@ -553,9 +554,21 @@ 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++;
+ cur_pos = 0;
+ is_valid = test_bit_le(0, raw_sit->valid_map) ? true : false;
+ 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);
}
>
>
> -----Original Message-----
> From: Chao Yu [mailto:[email protected]]
> Sent: Thursday, October 24, 2013 5:21 PM
> To: [email protected]
> Cc: [email protected]; '谭姝'; [email protected];
> [email protected]
> Subject: [f2fs-dev] [PATCH V2] 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.
>
> v2:
> use find_next_bit_le/find_next_zero_bit_le for better performance and
> readable as Jaegeuk suggested.
>
> Suggested-by: Jaegeuk Kim <[email protected]>
> Signed-off-by: Tan Shu <[email protected]>
> Signed-off-by: Yu Chao <[email protected]>
> ---
> fs/f2fs/segment.h | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index 7f94d78..d25b6af
> 100644
> --- a/fs/f2fs/segment.h
> +++ b/fs/f2fs/segment.h
> @@ -552,6 +552,23 @@ static inline void check_block_count(struct
> f2fs_sb_info *sbi,
> /* check boundary of a given segment number */
> BUG_ON(segno > end_segno);
>
> + /* check all ones or zeros valid_map */
> + if (GET_SIT_VBLOCKS(raw_sit) == 0) {
> + int pos = find_next_bit_le(&raw_sit->valid_map,
> + sbi->blocks_per_seg,
> + 0);
> + if (pos != sbi->blocks_per_seg)
> + BUG();
> + return;
> + } else if (GET_SIT_VBLOCKS(raw_sit) == sbi->blocks_per_seg) {
> + int pos = find_next_zero_bit_le(&raw_sit->valid_map,
> + sbi->blocks_per_seg,
> + 0);
> + if (pos != sbi->blocks_per_seg)
> + BUG();
> + return;
> + }
> +
> /* check bitmap with valid block count */
> for (i = 0; i < sbi->blocks_per_seg; i++)
> if (f2fs_test_bit(i, raw_sit->valid_map))
> --
> 1.7.9.5
>
>
> ------------------------------------------------------------------------------
> October Webinars: Code for Performance
> Free Intel webinars can help you accelerate application performance.
> Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from
> the latest Intel processors and coprocessors. See abstracts and register >
> http://pubads.g.doubleclick.net/gampad/clk?id=60135991&iu=/4140/ostg.clktr
> k
> _______________________________________________
> Linux-f2fs-devel mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel