Rockbox.org home
release
dev builds
extras
themes manual
wiki
device status forums
mailing lists
IRC bugs
patches
dev guide



Rockbox mail archive

Subject: Re: problems copying over many files
From: Johan Vromans (jvromans_at_squirrel.nl)
Date: 2003-03-29


"Gerald Clark" <gerald_clark_at_mindspring.com> writes:

> Are you running Linux and USB1 ?
> I suspect it starts out fast as it fills
> Many megs of buffers. When it runs out of buffers, it starts writing them.
> This is the long pause.

The following experiment confirms this.
Note these are figures for USB 2.0. Also note, that this is Linux
kernel 2.4.20.

 # mount /dev/sdd1 /mnt/tmp

Copy a directory with 120Mb (19 files):

 # time cp *.mp3 /mnt/tmp/tmp/
 0.020u 1.790s 0:28.33 6.3% 0+0k 0+0io 138pf+0w

Quickly, do it again:

 # time cp *.mp3 /mnt/tmp/tmp/
 0.010u 1.130s 0:03.21 35.5% 0+0k 0+0io 138pf+0w

Apparently, most of the data is still in the buffer.
Therefore, the umount needs time to flush:

 # time umount /dev/sdd1
 0.000u 0.410s 0:22.20 1.8% 0+0k 0+0io 145pf+0w

These are the figures for USB 1:

 # mount /dev/sdd1 /mnt/tmp
 # cp *.mp3 /mnt/tmp/tmp/
 0.030u 1.130s 3:00.24 0.6% 0+0k 0+0io 130pf+0w
 # time umount /dev/sdd1
 0.010u 0.340s 2:29.06 0.2% 0+0k 0+0io 145pf+0w

-- Johan



Page was last modified "Jan 10 2012" The Rockbox Crew
aaa