lfs_bd_cmp() compares more bytes at one time #395
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
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>
|
This looks reasonable to me.... |
thrasher8390
approved these changes
Mar 24, 2020
| uint8_t dat; | ||
| int err = lfs_bd_read(lfs, | ||
| for (lfs_off_t i = 0; i < size; i += diff) { | ||
| uint8_t dat[8]; |
There was a problem hiding this comment.
Why was 8 chosen.
Remember that this is being stored on the stack.
Any thoughts on making this configurable or reasons why it shouldn't be configurable?
There was a problem hiding this comment.
Too many configurations can be confusing.
I think 8 bytes is the best balance between performance and used space.
|
Hi @gmpy, this is a great patch and great analysis! Sorry this PR has been hanging for so long. I wasn't able to make a release for a while, but will bring this in the next minor release. |
geky
approved these changes
Nov 16, 2020
This was referenced Dec 4, 2020
Merged
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
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