Hi...Can anyone please guide me on FIFO Pipes in UNIX.I have lerant things like creating fifo pipes,using them for reads and writes etc.I want to know what is the maximum amount of memory that such a pipe may have? Also can anyone guide me on where to get info on this topic from?
pipes are special files.
Are you asking how much data can I place in a pipe at one time?
Yes, I would like to know how much data can a named pipe hold in case one file keeps on writing to the pipe while no file reads the data...
When you direct data to a pipe, I/O is always blocked and the only buffering is that performed by the pipe. It is the responsibility of the monitoring application to promptly read the data from the pipe as the event monitor writes the event data. If the event monitor is unable to write the data to the pipe (for example, because the pipe is full), monitor data will be lost.
In addition, there must be enough space in the named pipe to handle incoming event records. If the application does not read the data from the named pipe fast enough, the pipe will fill up and overflow. The smaller the pipe buffer, the greater the chance of an overflow.
When a pipe overflow occurs, the monitor creates overflow event records indicating that an overflow has occurred. The event monitor is not turned off, but monitor data is lost. If there are outstanding overflow event records when the monitor is deactivated, a diagnostic message will be logged. Otherwise, the overflow event records will be written to the pipe when possible.
If your operating system allows you to define the size of the pipe buffer, use a pipe buffer of at least 32K. For high-volume event monitors, you should set the monitoring application's process priority equal to or higher than the agent process priority.
hope this help you!
andwhat
hi thanks a lot for the reply...
well from what I got to know it seems that to change the pipe buffer size I need to effect changes and then recompile my kernel....
is there any way by which i can actually view the pipe buffer size....(just view it and not change it...) ?
thanks in advance.........