WeiXiong Liao 64f70f51b0 lfs_bd_cmp() compares more bytes at one time ...

It's very slowly to compare one byte at one time. Here are the
performance I get from 128M spinand with NFTL by sequential writing.

| file size | buffer size  | write speed  |
| 10 MB     | 0   B        | 3206.01 KB/s |
| 10 MB     | 1   B        | 2434.04 KB/s |
| 10 MB     | 2   B        | 2685.78 KB/s |
| 10 MB     | 4   B        | 2857.94 KB/s |
| 10 MB     | 8   B        | 3060.68 KB/s |
| 10 MB     | 16  B        | 3155.30 KB/s |
| 10 MB     | 64  B        | 3193.68 KB/s |
| 10 MB     | 128 B        | 3230.62 KB/s |
| 10 MB     | 256 B        | 3153.03 KB/s |

| 70 MB     | 0   B        | 2258.87 KB/s |
| 70 MB     | 1   B        | 1827.83 KB/s |
| 70 MB     | 2   B        | 1962.29 KB/s |
| 70 MB     | 4   B        | 2074.01 KB/s |
| 70 MB     | 8   B        | 2147.03 KB/s |
| 70 MB     | 64  B        | 2179.92 KB/s |
| 70 MB     | 256 B        | 2179.96 KB/s |

The 0 Byte size means no validation and the 1 Byte size is how
littlefs do before. Based on the above table and to save memory,
comparing 8 bytes at one time is more wonderful.

Signed-off-by: WeiXiong Liao <liaoweixiong@allwinnertech.com>

2020-03-13 15:23:20 +08:00

144 KiB

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