Re: HOW TO INCREASE FIFO SIZE LIMIT?

From: Michael Kerrisk (michael-dot-kerrisk-at-gmx-dot-net_at_NOSPAM.COM)
Date: 01/20/04 

Date: Tue, 20 Jan 2004 09:25:42 +0100

On 19 Jan 2004 16:16:35 -0800, sandeep_onsite@yahoo.com (Sandeep)
wrote:

>Hi,
>
>Does anybody know how to increase FIFO Max. size limit on RedHat 9.0?
>My current limit is 8*512 bytes, which is as shown by "ulimit -p" command.
>I tried to increase it to 20*512 bytes using command: "ulimit -p 20".
>Got this error:
>
>ulimit: pipe size: cannot modify limit: Invalid argument
>
>Let me know is there is any other way to change the Max. size of Fifo/Pipe?

Hello Sandeep,

There is no way to do this with a standard kernel (the bash man page
explicitly notes that you can't set this limit). There are patches
around that allow you to rebuild the kernel with a different value for
this limit. However, doing this is almost certainly a bad idea: an
application built with such a kernel dependency won't be portable.
Furthermore, looking for this facility is usually an indicator of bad
application design: In general, an application should never need to be
concerned with exactly what the capacity of a pipe is -- if we want to
prevent the writer process from blocking, the process reading from the
pipe should be designed to read data as soon as it available.

It might be a good idea if you explain what you want to do and why.
Then people might be able to make suggestions about better ways of
solving the problem.

Cheers,

Michael

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