toolchain/47562: very slow installworld

[martin%NetBSD.org@localhost]

>Number:         47562
>Category:       toolchain
>Synopsis:       very slow installworld
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    toolchain-manager
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Wed Feb 13 11:00:01 +0000 2013
>Originator:     Martin Husemann
>Release:        NetBSD 6.99.16
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD thirdstage.duskware.de 6.99.16 NetBSD 6.99.16 (MODULAR) #40: Tue 
Feb 5 20:22:09 CET 2013 
martin%night-porter.duskware.de@localhost:/usr/src/sys/arch/sparc64/compile/MODULAR
 sparc64
Architecture: sparc64
Machine: sparc64
>Description:

Recent changes to mtree/sets installation caused a significant slowdown
of "make installworld", maybe due to a lot of hashes being calculated
and then ignored?

I often mount the source tree and a prebuild DESTDIR via nfs, then do
a "make installworld" on the NFS client machine.

It then does:

installsets ===> distrib/sets   (with: INSTALLDIR=/ INSTALLSETS=)
cd /usr/src/distrib/sets &&  DESTDIR=/mnt  MACHINE=sparc64  
MACHINE_ARCH=sparc64  AWK=awk  CKSUM=cksum  DB=db  HOST_SH=/bin/sh  MAKE=make  
MKTEMP=mktemp  MTREE=mtree  PAX=pax  COMPRESS_PROGRAM=gzip  
PKG_CREATE=pkg_create  SED=sed  TSORT=tsort\ -q  /bin/sh ./maketars -d /mnt    
-N /usr/src/etc  -L base,x -i / 
{*LONG PAUSE HERE*}
Copying set base
Copying set comp
...

The "long pause" was there before, but it got significantly longer recently
and on slower machines now can be in the hours magnitude.

I assume this time is spent calculating hash values for mtree output, which
is not realy used during this procedure. While uniformication of the process
is good, this might be a case for an exception.

>How-To-Repeat:
make installworld on a m68k machine ;-)

>Fix:
n/a