Re: Linux-Netbsd huge difference of speed, same hardware

[Pierre Dupond <76nemo76%gmx.ch@localhost>]

Thanks for the tip. It is a little bit faster now
but still much less fast than  with Linux. Why the use
of the raw device makes a difference.

The transcript of the commands when using
the raw device is:

oche# dd if=/dev/urandom of=/dev/rld0f bs=32k count=1000
1000+0 records in
1000+0 records out
32768000 bytes transferred in 7.726 secs (4241263 bytes/sec)
oche# dd if=/dev/urandom of=/dev/rld0f bs=32k count=10000
10000+0 records in
10000+0 records out
327680000 bytes transferred in 90.755 secs (3610599 bytes/sec)
oche# ^C
oche# dd if=/dev/urandom of=/dev/rld0f bs=2m count=100
100+0 records in
100+0 records out
209715200 bytes transferred in 45.064 secs (4653719 bytes/sec)

Le 04.03.20 à 08:20, Martin Husemann a écrit :
> On Wed, Mar 04, 2020 at 08:08:34AM +0100, Pierre Dupond wrote:
>> I try to execute the command "dd if=/dev/urandom of=/dev/ld0f bs=2m" (or "bs=32k" but
>> this make no difference).
>
> You want of=/dev/rld0f here.
>
> Also I dimly remember gnu dd not flushing the output or something unless
> some special option is given, but that should not make a real difference for
> huge transfers.
>
> Martin
>