mod_cgi/9676: reading from CGI programs is very inefficient

[David MacKenzie <dj...@pix.net>]

>Number:         9676
>Category:       mod_cgi
>Synopsis:       reading from CGI programs is very inefficient
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    apache
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   apache
>Arrival-Date:   Thu Jan 31 20:00:00 PST 2002
>Closed-Date:
>Last-Modified:
>Originator:     djm@pix.net
>Release:        2.0.18 and CVS
>Organization:
apache
>Environment:
Unix (BSDI BSD/OS 4.3)
>Description:
Apache 2 does at least one read() system call for every byte that it reads from a CGI program.  Ouch!  It seems that the stream is unbuffered and apr_file_gets() calls apr_file_read() once per byte; including timeouts, it can be more than one read() per byte!
>How-To-Repeat:
Add some diagnostics to srclib/apr/file_io/unix/readwrite.c or do a system call trace when running a simple CGI program (e.g., printenv).
>Fix:
Perhaps there's some confusion between nonblocking and unbuffered.  Although the CGI pipe may have to be nonblocking, is there any reason that apr_file_read() shouldn't read ahead and buffer as much as it can get (up to some arbitrary limit), even when it's only being asked for 1 byte at a time?

>Release-Note:
>Audit-Trail:
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