diff options
author | Richard Tollerton <rich.tollerton@ni.com> | 2014-12-08 17:13:35 -0600 |
---|---|---|
committer | Richard Purdie <richard.purdie@linuxfoundation.org> | 2014-12-19 17:54:14 +0000 |
commit | e8ea6a29ed3ab9892a3bc7ee8249f10688c0af29 (patch) | |
tree | c890649b03de4f96116dc1bfe1a0ca806ba88d11 /meta/recipes-core/udev/udev/init | |
parent | 107e7fa2b2cc2e06addb83518c03b3ab769fed6f (diff) | |
download | openembedded-core-contrib-e8ea6a29ed3ab9892a3bc7ee8249f10688c0af29.tar.gz |
udev-cache: replace readfiles() with cmp
Currently, udev-cache system configurations are compared as shell string
variables, read into memory with the readfiles() function. This is more
complex, and significantly (27-41%) slower, than comparing them using
`cmp`. (Performance was verified on both Cortex-A9 and Intel Nehalem
systems.)
So just use cmp. This requires a few other small changes:
exclude /proc/atags from CMP_FILE_LIST if it doesn't exist to avoid
errors in `cat` and `cmp`.
`cmp -q` doesn't exist in busybox, so instead, redirect output to
/dev/null.
Signed-off-by: Richard Tollerton <rich.tollerton@ni.com>
Diffstat (limited to 'meta/recipes-core/udev/udev/init')
-rw-r--r-- | meta/recipes-core/udev/udev/init | 29 |
1 files changed, 7 insertions, 22 deletions
diff --git a/meta/recipes-core/udev/udev/init b/meta/recipes-core/udev/udev/init index d26cbfca96..ee7967063a 100644 --- a/meta/recipes-core/udev/udev/init +++ b/meta/recipes-core/udev/udev/init @@ -20,17 +20,6 @@ SYSCONF_TMP="/dev/shm/udev.cache" [ -f /etc/udev/udev.conf ] && . /etc/udev/udev.conf [ -f /etc/default/rcS ] && . /etc/default/rcS -readfiles () { - READDATA="" - for filename in $@; do - if [ -r $filename ]; then - while read line; do - READDATA="$READDATA$line" - done < $filename - fi - done -} - kill_udevd () { pid=`pidof -x udevd` [ -n "$pid" ] && kill $pid @@ -63,14 +52,12 @@ case "$1" in # Cache handling. # A list of files which are used as a criteria to judge whether the udev cache could be reused. - CMP_FILE_LIST="/proc/version /proc/cmdline /proc/devices /proc/atags" + CMP_FILE_LIST="/proc/version /proc/cmdline /proc/devices" + [ -f /proc/atags ] && CMP_FILE_LIST="$CMP_FILE_LIST /proc/atags" if [ "$DEVCACHE" != "" ]; then if [ -e $DEVCACHE ]; then - readfiles $CMP_FILE_LIST - NEWDATA="$READDATA" - readfiles "$SYSCONF_CACHED" - OLDDATA="$READDATA" - if [ "$OLDDATA" = "$NEWDATA" ]; then + cat -- "$CMP_FILE_LIST" > "$SYSCONF_TMP" + if cmp $SYSCONF_CACHED $SYSCONF_TMP >/dev/null; then tar xmf $DEVCACHE -C / -m not_first_boot=1 [ "$VERBOSE" != "no" ] && echo "udev: using cache file $DEVCACHE" @@ -80,17 +67,15 @@ case "$1" in if [ "$VERBOSE" != "no" ]; then echo "udev: udev cache not used" echo "udev: we use $CMP_FILE_LIST as criteria to judge whether the cache /dev could be resued" - echo "udev: olddata: $OLDDATA" - echo "udev: newdata: $NEWDATA" + echo "udev: cached sysconf: $SYSCONF_CACHED" + echo "udev: current sysconf: $SYSCONF_TMP" fi - echo "$NEWDATA" > "$SYSCONF_TMP" fi else if [ "$ROOTFS_READ_ONLY" != "yes" ]; then # If rootfs is not read-only, it's possible that a new udev cache would be generated; # otherwise, we do not bother to read files. - readfiles $CMP_FILE_LIST - echo "$READDATA" > "$SYSCONF_TMP" + cat -- "$CMP_FILE_LIST" > "$SYSCONF_TMP" fi fi fi |