On 8/21/25 10:40, Jiucheng Xu via B4 Relay wrote:
> From: Tao Zeng <tao.z...@amlogic.com>
>
> Always do checkpoint is a heavy behavior for compressed file.
> But for contiguous writing of a file, checkpoint need to be
> skipped to help improve performance.
>
> Tested with iozone for always do check point on compressed data,
> results are:
>
> File stride size set to 17 * record size.
> random random
> KB reclen write rewrite read reread read write
> 102400 4 1314 35488 234231 1683793 1212394 35334
> 102400 8 2387 54133 244584 1871789 1644952 52478
> 102400 16 5060 7059 298052 1901792 1894929 6600
> 102400 32 9315 13118 424723 1825565 1924235 12041
> 102400 64 17028 22258 491181 1844443 1968247 22115
> 102400 128 30551 38008 445192 1796615 1917466 38527
> 102400 256 46944 55006 509625 1630910 1715586 56201
> 102400 512 63355 70432 434639 1406089 1487569 72718
> 102400 1024 83036 86742 447141 1420505 1503320 88913
> 102400 2048 98577 101971 450287 1434918 1522294 106374
> 102400 4096 113300 116994 451286 1435321 1527404 119579
> 102400 8192 132532 133044 488503 1458688 1540595 141167
> 102400 16384 143246 143857 489376 1469878 1556530 151362
>
> We can see that writing speed of small pieces of data(less than 16KB) is
> very slow.
>
> With this change, iozone data are on the same hardware:
> random random
> KB reclen write rewrite read reread read write
> 102400 4 14658 34796 232797 1985764 1219513 34509
> 102400 8 25980 53695 233218 2419198 1788989 51927
> 102400 16 49556 50325 266754 2780871 2256746 50593
> 102400 32 79947 80783 393452 2755413 2467949 77681
> 102400 64 104866 105830 531853 2816504 2596812 106223
> 102400 128 142097 142034 651876 2885805 2728473 143296
> 102400 256 146972 144822 535727 2542080 2450922 157390
> 102400 512 126591 152480 571581 2055442 2052839 156512
> 102400 1024 135164 143667 654547 2052594 2045214 130488
> 102400 2048 127587 124889 491258 2058457 2059454 141273
> 102400 4096 124280 123959 660713 2067394 2056889 131967
> 102400 8192 138240 136233 509709 2102040 2090773 149215
> 102400 16384 146524 145333 576519 2118162 2096482 158704
>
> We can see that speed of write with small pieces of data increased a lot.
>
> Signed-off-by: Tao Zeng <tao.z...@amlogic.com>
> Signed-off-by: Jiucheng Xu <jiucheng...@amlogic.com>
> ---
> fs/f2fs/f2fs.h | 1 +
> fs/f2fs/file.c | 18 ++++++++++++++----
> 2 files changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index
> d6a49de1b7e919eda12354c074b8b253b2a9ea3f..2f820d531cdb32c0fc050aca05ffd3d00395a618
> 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1531,6 +1531,7 @@ enum compress_algorithm_type {
>
> enum compress_flag {
> COMPRESS_CHKSUM,
> + COMPRESS_SKIP_WRITE_CP,
> COMPRESS_MAX_FLAG,
> };
>
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index
> 42faaed6a02da01f2bd117a5c55e1761beaffde6..3561b407f45e7aa97c7dcf911d4dddbc01ec2ca4
> 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -212,7 +212,9 @@ static inline enum cp_reason_type
> need_do_checkpoint(struct inode *inode)
>
> if (!S_ISREG(inode->i_mode))
> cp_reason = CP_NON_REGULAR;
> - else if (f2fs_compressed_file(inode))
> + else if (f2fs_compressed_file(inode) &&
> + !(F2FS_I(inode)->i_compress_flag &
> + BIT(COMPRESS_SKIP_WRITE_CP)))
> cp_reason = CP_COMPRESSED;
IIRC, we can not avoid checkpoint for fsync on compressed file w/ this way,
since we haven't supported compressed file recovery yet.
You can check this w/ the way as below:
write -> fsync -> shutdown -> recovery -> check data&meta
Thanks,
> else if (inode->i_nlink != 1)
> cp_reason = CP_HARDLINK;
> @@ -5234,6 +5236,11 @@ static ssize_t f2fs_file_write_iter(struct kiocb
> *iocb, struct iov_iter *from)
> f2fs_dio_write_iter(iocb, from, &may_need_sync) :
> f2fs_buffered_write_iter(iocb, from);
>
> + /* skip checkpoint for normal write compress file */
> + if (f2fs_compressed_file(inode))
> + F2FS_I(inode)->i_compress_flag |=
> + BIT(COMPRESS_SKIP_WRITE_CP);
> +
> trace_f2fs_datawrite_end(inode, orig_pos, ret);
> }
>
> @@ -5250,14 +5257,17 @@ static ssize_t f2fs_file_write_iter(struct kiocb
> *iocb, struct iov_iter *from)
> }
>
> clear_inode_flag(inode, FI_PREALLOCATED_ALL);
> +
> + if (ret > 0 && may_need_sync)
> + ret = generic_write_sync(iocb, ret);
> +
> + if (f2fs_compressed_file(inode))
> + F2FS_I(inode)->i_compress_flag &= ~BIT(COMPRESS_SKIP_WRITE_CP);
> out_unlock:
> inode_unlock(inode);
> out:
> trace_f2fs_file_write_iter(inode, orig_pos, orig_count, ret);
>
> - if (ret > 0 && may_need_sync)
> - ret = generic_write_sync(iocb, ret);
> -
> /* If buffered IO was forced, flush and drop the data from
> * the page cache to preserve O_DIRECT semantics
> */
>
> ---
> base-commit: 3ea4ad0a1df0bcbfd5ccdcea56d57ca4678ae2a8
> change-id: 20250820-dev-31b792e8e1fb
>
> Best regards,
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