[fpc-pascal] TProcess read buffer size

[Ryan Joseph]

> On Jul 15, 2021, at 8:33 PM, Dennis Lee Bieber via fpc-pascal <fpc-pascal at lists.freepascal.org> wrote:
> 
> https://flylib.com/books/en/3.126.1.111/1/
> 
> """
> Only writes below PIPE_BUF bytes in size are guaranteed to be atomic.
> PIPE_BUF is 512 bytes on Mac OS X. The fpathconf() system call can be used
> to retrieve the value of PIPE_BUF given a pipe descriptor.
> """
> 
> 	Granted you seem to be reading -- but the other end may be what is
> controlling the size of each packet (and may somehow even have set the pipe
> overall size to just one "buffer").
> 
> 	Unless you can examine the writing side, or source code of your read
> method...

Yes I think you're right.

~$ ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
file size               (blocks, -f) unlimited
max locked memory       (kbytes, -l) unlimited
max memory size         (kbytes, -m) unlimited
open files                      (-n) 256
pipe size            (512 bytes, -p) 1
stack size              (kbytes, -s) 8192
cpu time               (seconds, -t) unlimited
max user processes              (-u) 2784
virtual memory          (kbytes, -v) unlimited


It's just a PHP script that dumps 64k chunks but if the pipe buffer is 512b then I'm stuck. Is there a lower level library I can use to set the pipe size? I was curious if this is a bottle neck for me. Currently it takes about 7 seconds to read a 600MB file from one process to another, which is insanely slow.

Regards,
	Ryan Joseph