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

[Martin Husemann <martin%duskware.de@localhost>]

On Wed, Mar 04, 2020 at 10:07:29AM +0100, Pierre Dupond wrote:
> Thanks for the tip. It is a little bit faster now
> but still much less fast than  with Linux.

Just out of curiosity, why are you mising in /dev/urandom here?
For performance measurements probably /dev/zero is better (but I don't
know if SD cards optimize all-zero blocks).

Is the speed of the card properly detected (i.e. does the dmesg part
you posted match the marketing numbers from the manufacturer)?

> Why the use of the raw device makes a difference.

It avoids another level of buffering in the kernel.

Martin