#10045 HIGH 1.5-sof: XO-1.5 Record audio/video are out of sync with each other

James Cameron quozl at laptop.org
Mon May 10 20:23:38 EDT 2010


On Mon, May 10, 2010 at 12:45:45PM -0400, Martin Langhoff wrote:
> On Mon, May 10, 2010 at 2:37 AM, James Cameron <quozl at laptop.org> wrote:
> > I've no explanation for this behaviour.
> 
> Do we still have some (sugar?) log files opened 'sync'? ext3/4 still
> 'fsync' the whole partition, which may explain the erratic
> performance.

No, no Sugar log files are opened O_SYNC at the moment.  I fixed that.

The test also reproduces without Sugar running, and also in single user
mode.  This excludes Sugar and all user-space, suggesting the problem is
isolatable to or a combination of kernel, hardware and media.

--

#!/bin/sh
# test filesystem write
echo 1 > /proc/sys/vm/drop_caches 
echo 2 > /proc/sys/vm/drop_caches 
echo 3 > /proc/sys/vm/drop_caches 
time strace -o /tmp/k -e write -T dd if=/dev/zero of=/root/file bs=8192 count=32000
time sync
grep write /tmp/k|cut -f2 -d'<'|cut -f1 -d'>'|sort -rn|more

-- 
James Cameron
http://quozl.linux.org.au/


More information about the Devel mailing list