mirror of
https://github.com/uutils/coreutils
synced 2024-12-17 16:43:16 +00:00
35 lines
2 KiB
Markdown
35 lines
2 KiB
Markdown
|
# Benchmarking ls
|
||
|
|
|
||
|
|
ls majorly involves fetching a lot of details (depending upon what details are requested, eg. time/date, inode details, etc) for each path using system calls. Ideally, any system call should be done only once for each of the paths - not adhering to this principle leads to a lot of system call overhead multiplying and bubbling up, especially for recursive ls, therefore it is important to always benchmark multiple scenarios.
|
||
|
|
This is an overwiew over what was benchmarked, and if you make changes to `ls`, you are encouraged to check
|
||
|
|
how performance was affected for the workloads listed below. Feel free to add other workloads to the
|
||
|
|
list that we should improve / make sure not to regress.
|
||
|
|
|
||
|
|
Run `cargo build --release` before benchmarking after you make a change!
|
||
|
|
|
||
|
|
## Simple recursive ls
|
||
|
|
|
||
|
|
- Get a large tree, for example linux kernel source tree.
|
||
|
|
- Benchmark simple recursive ls with hyperfine: `hyperfine --warmup 2 "target/release/coreutils ls -R tree > /dev/null"`.
|
||
|
|
|
||
|
|
## Recursive ls with all and long options
|
||
|
|
|
||
|
|
- Same tree as above
|
||
|
|
- Benchmark recursive ls with -al -R options with hyperfine: `hyperfine --warmup 2 "target/release/coreutils ls -al -R tree > /dev/null"`.
|
||
|
|
|
||
|
|
## Comparing with GNU ls
|
||
|
|
|
||
|
|
Hyperfine accepts multiple commands to run and will compare them. To compare performance with GNU ls
|
||
|
|
duplicate the string you passed to hyperfine but remove the `target/release/coreutils` bit from it.
|
||
|
|
|
||
|
|
Example: `hyperfine --warmup 2 "target/release/coreutils ls -al -R tree > /dev/null"` becomes
|
||
|
|
`hyperfine --warmup 2 "target/release/coreutils ls -al -R tree > /dev/null" "ls -al -R tree > /dev/null"`
|
||
|
|
(This assumes GNU ls is installed as `ls`)
|
||
|
|
|
||
|
|
This can also be used to compare with version of ls built before your changes to ensure your change does not regress this
|
||
|
|
|
||
|
|
## Checking system call count
|
||
|
|
|
||
|
|
- Another thing to look at would be system calls count using strace (on linux) or equivalent on other operating systems.
|
||
|
|
- Example: `strace -c target/release/coreutils ls -al -R tree`
|