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List:       apache-httpd-dev
Subject:    Re: CGI brigades
From:       Greg Ames <gregames () apache ! org>
Date:       2003-01-31 18:23:21
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Dietz, Phil E. wrote:
> I just read this:
> 
> * pipes deadlock on all platforms with limited pipe buffers (e.g. both
> Linux and Win32, as opposed to only Win32 on 1.3).  The right solution
> is either GStein's proposal for a "CGI Brigade", or OtherBill's proposal
> for "Poll Buckets" for "Polling Filter Chains".  Or maybe both :-)
> 
> 
> I imagine this is in regards to stderr and stdout contending at the same time.
> 
> What if mod_cgi registered as output filter (the 1st one)...
> and all that filter did was :
> - read from the pipe bucket, convert it to a heap bucket, and passed it on to the \
>                 other output filters.....
> - stderr is read in and discarded...
> 
> Would this solve any of the issues ?

I don't see how it would if the CGI chooses writes to the stderr pipe until it 
blocks.  I believe mod_cgi would be blocked on the stdout pipe read.  If all the 
pipe reads in mod_cgi are made non-blocking, then we need some way to prevent 
busy wait loops.

Greg


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