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Path: utzoo!watmath!clyde!bonnie!akgua!sdcsvax!sdcrdcf!hplabs!hao!seismo!brl-tgr!tgr!speck@cit-vax
From: speck@brl-tgr.ARPA
Newsgroups: net.unix-wizards
Subject: Reduce /etc/dump user CPU time by 65%
Message-ID: <6504@brl-tgr.ARPA>
Date: Wed, 12-Dec-84 02:07:33 EST
Article-I.D.: brl-tgr.6504
Posted: Wed Dec 12 02:07:33 1984
Date-Received: Wed, 19-Dec-84 00:16:19 EST
Sender: news@brl-tgr.ARPA
Organization: Ballistic Research Lab
Lines: 14

Index:		etc/dump/dumptape.c (4.2BSD)
Description:	'dump' spends over 2/3 of its user time
		copying 1K-byte arrays inefficiently.
Fix:	Replace the slow code with a structure copy (uses movc3 on vax).
	diff old/dumptape.c dumptape.c
	30,33c30
	<	register i;
	<
	<	for (i=0; i < TP_BSIZE; i++)
	<		tblock[trecno][i] = *dp++;
	---
	>	*(union u_spcl *)(tblock[trecno]) = *(union u_spcl *)dp;
--------
    Don Speck	"Cryptic?  Why do you think they call it CODE?"