Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!rutgers!ames!oliveb!jerry
From: jerry@oliveb.UUCP (Jerry F Aguirre)
Newsgroups: news.software.b
Subject: Re: 2.11 efficiency problem
Message-ID: <851@oliveb.UUCP>
Date: Mon, 20-Apr-87 17:54:17 EST
Article-I.D.: oliveb.851
Posted: Mon Apr 20 17:54:17 1987
Date-Received: Tue, 21-Apr-87 05:38:04 EST
References: <330@dcl-csvax.comp.lancs.ac.uk>
Reply-To: jerry@oliveb.UUCP (Jerry F Aguirre)
Distribution: world
Organization: Olivetti ATC; Cupertino, Ca
Lines: 35

In article <330@dcl-csvax.comp.lancs.ac.uk> stephen@comp.lancs.ac.uk (Stephen J. Muir) writes:
>I find that inews spends a vast amount of *CPU* time copying each article of a
>batch to a temporary file -- something like several minutes to copy about 50K
>bytes of a single article (this takes about 15 minutes real time for a single
>article at the moment with the load at 5.0).  I simply cannot believe it can be
>so inefficient!  It was a *lot* faster when it forked "unbatch".

Before submitting the code in question I ran a performance comparison
with the following results:

	unbatch  9.6u 5.2s 0:23 63% 41+69k 80+160io 62pf+0w
	    new  5.5u 3.6s 0:12 71% 68+115k 44+126io 6pf+0w

This was for a uncompressed batch consisting of 6 articles all of which
were rejected as duplicates.  (This was the only way I could get a
repeatable test.) This is significantly faster than the "unbatch" code.

The code was beset with a number of compatability problems related to
buffering and reposition of the input.  In the infamous patch number 6
someone added a "setbuf(infp, NULL") to the  begining of the checkbatch
routine.  A shotgun fix to a subtle problem.  As far as I can figure out
this results in the copy being fread a byte at a time.  (The usual
idiocy of using buffered IO routines (getc) to do unbuffered IO!)

If the batch was in '#! cunbatch' format then this problem will not
occur because the buffering will be restored.  (Most of my news is in
this format.)

I will work on a fix.  Actually, I kind of like the setbuf...NULL as I
wanted to use read instead of fread anyway.  Always nice to get back to
basics.

					Jerry Aguirre

(Never install an even numbered patch!)