[omgps] collect feature requests
Rask Ingemann Lambertsen
ccc94453 at vip.cybercity.dk
Mon Jul 13 03:03:08 CEST 2009
On Tue, Jun 30, 2009 at 11:32:39PM +0200, Laszlo KREKACS wrote:
> I already wrote about it about a month ago:
> http://lists.openmoko.org/pipermail/community/2009-June/048997.html
So you've found that vfat, ext2 and ext3 aren't very good (for storing
map tiles)? How about using reiserfs instead?
> Remember accessing invidual files on a sd card takes time. A lot.
> You can try it for yourself, copy to a pendrive your ~/Maps directory.
> Now tar the dir (Maps.tar) and copy that singly file to the pendrive.
>
> The result is something like 40sec compared to 6-7min.
I cannot reproduce that huge time difference, I get more like +50 % than
+900 %:
time (s) space left (MB)
fs/blocksize cp tar cp tar
ext3/1024 242 162 405 404
reiserfs/1024 305 193 426 421
ext3/2048 208 143 397 404
reiserfs/2048 264 161 415 414
ext3/4096 193 131 376 398
reiserfs/4096 242 156 394 398
I used the script below on my Freerunner with a USB card reader and the
512 MB uSD card that came with the Freerunner. I used the default journal size
for both ext3 and reiserfs. I guess you would want to reduce that.
#!/bin/sh
# Compare file system suitability for storing map tiles
# with that of a tar archive in terms of speed and
# space efficiency.
TILESOURCE=/usr/local/share/maptiles/openstreetmap
TESTDEV=/dev/sda2
TESTMOUNT=/mnt/flash
OPTS_ext3='-q -T small -m 0 -b 4096'
OPTS_reiserfs='-q -b 4096'
for fs in ext3 reiserfs; do
eval 'FSOPTS=${OPTS_'${fs}':-}'
for i in 1 2; do
mkfs.${fs} ${FSOPTS} ${TESTDEV}
mount ${TESTDEV} ${TESTMOUNT}
START=$(date +%s)
tar -cf ${TESTMOUNT}/OSM.tar ${TILESOURCE}
df -h ${TESTMOUNT}
umount ${TESTDEV}
FINISH=$(date +%s)
echo "Tar test ${i} on ${fs} took $((${FINISH} - ${START})) s."
done
for i in 1 2; do
mkfs.${fs} ${FSOPTS} ${TESTDEV}
mount ${TESTDEV} ${TESTMOUNT}
START=$(date +%s)
cp -a ${TILESOURCE} ${TESTMOUNT}/OSM
df -h ${TESTMOUNT}
umount ${TESTDEV}
FINISH=$(date +%s)
echo "Cp test ${i} on ${fs} took $((${FINISH} - ${START})) s."
done
done
--
Rask Ingemann Lambertsen
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