4 ms·

The link isn't working for me. For those who were able to see it: does it improve anything by using that instead of what ls does now??

Imustaskforhelp 1y ago
Hm interesting, it worked for me.
ta988 1y ago
70% faster, but more importantly 35x times less syscalls.
- eviks 1y ago
  Is there a noticeable benefit of this huge syscall reduction?
  - Imustaskforhelp 1y ago
    Yes I just checked it after installing strace strace -c ls gave me this 100.00 0.002709 13 198 5 total strace -c eza gave me this 100.00 0.006125 12 476 48 total strace -c lsr gave me this 100.00 0.001277 33 38 total So seeing the number of syscalls in the calls directory 198 : ls 476 : eza 33 : lsr A meaningful difference indeed!
    - richardwhiuk 1y ago
      That's just observing there is a difference, not explaining why that's a good thing.
      - fpoling 1y ago
        syscalls are expensive and their relative latency compared with the rest of code only grow especially in view of mitigations against cache-related and other other hardware bugs.
- loeg 1y ago
  Why do you say more importantly? The time is all that matters, I think.
  - plq 1y ago
    %70 faster = you wait less 35x less system calls = others wait less for the kernel to handle their system calls
    - loeg 1y ago
      > 35x less system calls = others wait less for the kernel to handle their system calls That isn't how it works. There isn't a fixed syscall budget distributed among running programs. Internally, the kernel is taking many of the same locks and resources to satisfy io_uring requests as ordinary syscall requests.
      - plq 1y ago
        More system calls mean more overall OS overhead eg. more context switches, or as you say more contention on internal locks etc. Also, more fs-related system calls mean less available kernel threads to process these system calls. eg. XFS can paralellize mutations only up to its number of allocation groups (agcount)
        loeg 1y ago
        > More system calls mean more overall OS overhead [than the equivalent operations performed with io_uring] Again, this just isn't true. The same "stat" operations are being performed one way or another. > Also, more fs-related system calls mean less available kernel threads to process these system calls. Generally speaking sync system calls are processed in the context of the calling (user) thread. They don't consume kernel threads generally. In fact the opposite is true here -- io_uring requests are serviced by an internal kernel thread pool, so to the extent this matters, io_uring requests consume more kernel threads.
        1y ago
rybosome 1y ago
It improves the latency of ls calls.

Imustaskforhelp 1y ago

Hm interesting, it worked for me.

ta988 1y ago

70% faster, but more importantly 35x times less syscalls.

eviks 1y ago
Is there a noticeable benefit of this huge syscall reduction?
- Imustaskforhelp 1y ago
  Yes I just checked it after installing strace strace -c ls gave me this 100.00 0.002709 13 198 5 total strace -c eza gave me this 100.00 0.006125 12 476 48 total strace -c lsr gave me this 100.00 0.001277 33 38 total So seeing the number of syscalls in the calls directory 198 : ls 476 : eza 33 : lsr A meaningful difference indeed!
  - richardwhiuk 1y ago
    That's just observing there is a difference, not explaining why that's a good thing.
    - fpoling 1y ago
      syscalls are expensive and their relative latency compared with the rest of code only grow especially in view of mitigations against cache-related and other other hardware bugs.
loeg 1y ago
Why do you say more importantly? The time is all that matters, I think.
- plq 1y ago
  %70 faster = you wait less 35x less system calls = others wait less for the kernel to handle their system calls
  - loeg 1y ago
    > 35x less system calls = others wait less for the kernel to handle their system calls That isn't how it works. There isn't a fixed syscall budget distributed among running programs. Internally, the kernel is taking many of the same locks and resources to satisfy io_uring requests as ordinary syscall requests.
    - plq 1y ago
      More system calls mean more overall OS overhead eg. more context switches, or as you say more contention on internal locks etc. Also, more fs-related system calls mean less available kernel threads to process these system calls. eg. XFS can paralellize mutations only up to its number of allocation groups (agcount)
      - loeg 1y ago
        > More system calls mean more overall OS overhead [than the equivalent operations performed with io_uring] Again, this just isn't true. The same "stat" operations are being performed one way or another. > Also, more fs-related system calls mean less available kernel threads to process these system calls. Generally speaking sync system calls are processed in the context of the calling (user) thread. They don't consume kernel threads generally. In fact the opposite is true here -- io_uring requests are serviced by an internal kernel thread pool, so to the extent this matters, io_uring requests consume more kernel threads.
        1y ago

rybosome 1y ago

It improves the latency of ls calls.