Re: [PATCH] Miniconfig revisited (2/3)
- From: Rob Landley <rob@xxxxxxxxxxx>
- Date: Sun, 9 Jul 2006 12:45:43 -0400
On Saturday 08 July 2006 12:21 pm, Horst von Brand wrote:
+LENGTH=$(cat .config | wc -l)
Why the cat(1)? "wc -l < .config" is the same
I believe it was originally a longer pipeline, and I can't wc the file
directly or it'll spit out the filename, but < is indeed one less process
spawned per loop.
+# Loop through all lines in the file
+I=1
+while true
+do
+ if [ $I -gt $LENGTH ]
+ then
+ break
+ fi
Could do it with:
for I in $(seq 1 $LENGTH); do
...
done
Makes a 1/10th of a second difference to the final runtime, but if you prefer
that...
or just plain read the lines
+
+ echo -n -e "\r"$I/$LENGTH lines $(cat "$OUTPUT" | wc -c) bytes
Again, unnecessary cat(1).
Yup, a valid cleanup.
The thing is, the script's going to be dog slow no matter what I do, and most
of the slowness isn't in the script, it's the config infrastructure
re-parsing the config file 1500 times or so for defconfig. (The script's
about 3% of the runtime overhead, and the two largest chunks of that are
printing out the progress indicator and the sed invocation right above the
make.) So I didn't put that much effort into optimizing it.
Someday I'd like to go in and make kconfig spit out a miniconfig directly, but
kconfig's not really set up to do that, and touching Roman Zippel's code
would give him the opportunity to say no again.
Anyway, here's a version with your fixes. Thanks for the review,
Rob
--
Never bet against the cheap plastic solution.
--- linux-2.6.17.1/scripts/shrinkconfig 2006-07-09 12:40:38.000000000 -0400
+++ linux-2.6.17.new/scripts/shrinkconfig 2006-07-09 12:12:32.000000000 -0400
@@ -0,0 +1,79 @@
+#!/bin/bash
+
+# shrinkconfig copyright 2006 by Rob Landley <rob@xxxxxxxxxxx>
+# Licensed under the GNU General Public License version 2.
+
+if [ $# -ne 1 ]
+then
+ echo "Turns current .config into a miniconfig file."
+ echo "Usage: shrinkconfig mini.config"
+ exit 1
+fi
+
+if [ ! -f .config ]
+then
+ echo "Need a .config file to shrink."
+ exit 1
+fi
+LENGTH=$(wc -l < .config)
+
+OUTPUT="$1"
+cp .config "$OUTPUT"
+if [ $? -ne 0 ]
+then
+ echo "Couldn't create $OUTPUT"
+ exit 1
+fi
+
+# If we get interrupted, clean up the mess
+
+KERNELOUTPUT=""
+
+function cleanup
+{
+ echo
+ echo "Interrupted."
+ [ ! -z "$KERNELOUTPUT" ] && rm -rf "$KERNELOUTPUT"
+ rm "$OUTPUT"
+ exit 1
+}
+
+trap cleanup HUP INT QUIT TERM
+
+# Since the "O=" argument to make doesn't work recursively, we need to jump
+# through a few hoops to avoid overwriting the .config that we're shrinking.
+
+# If we're building out of tree, we'll have absolute paths to source and build
+# directories in the Makefile.
+
+KERNELSRC=$(sed -n -e 's/KERNELSRC[^/]*:=[^/]*//p' Makefile)
+[ -z "$KERNELSRC" ] && KERNELSRC=$(pwd)
+KERNELOUTPUT=`pwd`/.config.minitemp
+
+mkdir -p "$KERNELOUTPUT" || exit 1
+
+echo "Shrinking .config to $OUTPUT..."
+
+for I in $(seq 1 $LENGTH)
+do
+ echo -n -e "\r"$I/$LENGTH lines $(wc -c < "$OUTPUT") bytes
+
+ sed -n "${I}!p" "$OUTPUT" > "$KERNELOUTPUT"/.config.test
+ # Do a config with this file
+ make -C "$KERNELSRC" O="$KERNELOUTPUT" allnoconfig KCONFIG_ALLCONFIG="$KERNELOUTPUT"/.config.test > /dev/null
+
+ # Compare. The date changes, so expect a small difference each time.
+ D=$(diff "$KERNELOUTPUT"/.config .config | wc -l)
+ if [ $D -eq 4 ]
+ then
+ mv "$KERNELOUTPUT"/.config.test "$OUTPUT"
+ LENGTH=$[$LENGTH-1]
+ else
+ I=$[$I + 1]
+ fi
+done
+
+rm -rf "$KERNELOUTPUT"
+
+# One extra echo to preserve status line.
+echo
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