Package: hotplug
Version: 0.0.20040329-22
Severity: wishlist
Tags: patch
Attached is a patch for '/etc/hotplug.d/default/default.hotplug'. It
replaces some loop code, (which on my system causes nine 'basename' piped
to 'sed' calls), with equivalent code that uses built-in POSIX shell
parameter substitutions; substitutions work in 'ash', 'dash', 'bash',
and so forth -- all the Debian boot shells.
The benefit is that there's no need to make pipes or spawn shells, since the
parsing functions are already in memory.
Note: I wrote this tweak after reading about 'hotplug-perl':
http://opensource.idealcorp.com/hotplug-perl/
...where its author reports that on his system "hotplug-perl reduced the
boot time by 53 seconds making the init to X Window time approximately
47 seconds".
It got me wondering, "what can perl do that's so much faster?", so I
looked at some 'hotplug' code, and this is the first obvious tweak I
noticed. Mabye other similar tweaks can be done...
Another thing -- in theory the shell script 'hotplug' might be made
faster than the 'perl' version; all other things being equal, any shell
interpreter needs less RAM than 'perl'; so any CPU would cache it
better.
Hope this helps...
-- System Information:
Debian Release: 3.1
APT prefers unstable
APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: i386 (i686)
Shell: /bin/sh linked to /bin/dash
Kernel: Linux 2.6.11-1-686
Locale: LANG=C, LC_CTYPE=C (charmap=ANSI_X3.4-1968) (ignored: LC_ALL set to C)
Versions of packages hotplug depends on:
ii bash 3.0-14 The GNU Bourne Again SHell
ii debconf 1.4.49 Debian configuration management sy
ii grep 2.5.1.ds1-4 GNU grep, egrep and fgrep
ii module-init-tools 3.2-pre1-2 tools for managing Linux kernel mo
ii modutils 2.4.27.0-3 Linux module utilities
ii procps 1:3.2.5-1 /proc file system utilities
ii sed 4.1.4-2 The GNU sed stream editor
-- debconf information excluded
--- /etc/hotplug.d/default/default.hotplug 2005-02-16 12:15:46.000000000
-0500
+++ /tmp/default.hotplug 2005-05-18 01:44:00.000000000 -0400
@@ -47,12 +47,12 @@
AGENTS=""
for AGENT in /etc/hotplug/*.agent ; do
- TYPE=`basename $AGENT | sed s/.agent//`
- if [ -x $AGENT ]; then
- AGENTS="$AGENTS $TYPE"
- else
- AGENTS="$AGENTS ($TYPE)"
+ TYPE=${AGENT##*/} # chop off path (like 'basename', but
cheaper)
+ TYPE=${TYPE%%.agent} # chop off extension
+ if [ ! -x $AGENT ]; then # not an exec?
+ TYPE="($TYPE)" # add parenthesis
fi
+ AGENTS="$AGENTS $TYPE"
done
echo "AgentName values on this system: $AGENTS"
else
