Subject: Re: fsync performance hit on 1.6.1
To: Daniel Brewer <>
From: Jochen Kunz <>
List: tech-kern
Date: 07/08/2003 12:41:45
On Tue, Jul 08, 2003 at 11:32:04AM +0200, Daniel Brewer wrote:

> Our system is a lot more complex than just 1 image source and 1 image sink.
> We have several other processes that may also require images. The file,
> although it may have its drawbacks, does allow multiple processes to use the
> same image data without replicating it all over the place.
Nearly the same for the product I am working for to get my bills payed.
We started the "Why don't we use a simple file?" way too. My coworkers
didn't want to get bothered with that "complicated" shared memory and 
semaphore thing. Meanwhile the requirements of the applicating got 
extended and we had to do the transition to a more sophisticated 
approach. I saw this coming when the shared memory approach was 
refused the first time.

You can share memory with several processes. E.g. one writes and 10 
other processes are reading it. You can have several independent 
shared memory areas. Every process can, but not must, participate
on a shared memory area. So a multiple writer multiple reader model
is doable. 

But all this goes OT now. I sugest a good book on Unix InterProcess
Communication. ;-)