cat: remove fcntl()

Author: oech3

src/uu/cat/src/splice.rs

@@ -24,9 +24,6 @@ pub(super) fn write_fast_using_splice<R: FdReadable, S: AsRawFd + AsFd>(
     write_fd: &S,
 ) -> CatResult<bool> {
     if splice(&handle.reader, &write_fd, MAX_ROOTLESS_PIPE_SIZE).is_ok() {
-        // fcntl improves throughput
-        // todo: avoid fcntl overhead for small input, but don't fcntl inside of the loop
-        let _ = rustix::pipe::fcntl_setpipe_size(write_fd, MAX_ROOTLESS_PIPE_SIZE);
         loop {
             match splice(&handle.reader, &write_fd, MAX_ROOTLESS_PIPE_SIZE) {
                 Ok(1..) => {}

src/uucore/src/lib/features/pipes.rs

@@ -22,8 +22,6 @@ pub const MAX_ROOTLESS_PIPE_SIZE: usize = 1024 * 1024;
 #[cfg(any(target_os = "linux", target_os = "android"))]
 pub fn pipe() -> std::io::Result<(File, File)> {
     let (read, write) = rustix::pipe::pipe()?;
-    // improve performance for splice
-    let _ = fcntl_setpipe_size(&read, MAX_ROOTLESS_PIPE_SIZE);
 
     Ok((File::from(read), File::from(write)))
 }