On Wed, 8 Jul 2020 12:47:22 -0700
Jason Thorpe <thorpej%me.com@localhost> wrote:
>
> > On Jul 8, 2020, at 11:51 AM, Sad Clouds
> > <cryintothebluesky%gmail.com@localhost> wrote:
> >
> > Sorry, don't have the answer to your question, but you mentioned
> > SSD on USB3, so wanted to ask if NetBSD on RPi4 is using USB3 to its
> > full potential? Some time ago I did a test with USB3 stick and
> > throughput was not very good.
>
> In order to fix that, someone is going to need to write a UAS / UASP
> driver for NetBSD. Right now, "umass" only supports CBI, CBI+CCI,
> and BBB/BOT.
>
> -- thorpej
>
Hi, I've just realised, the problem was actually USB3 flash stick, with
proper SSD it would have been much better.
I have SanDisk Ultra Fit 64 GB and it turns out write throughput is
capped at 40 MiB/sec, which I assume is due to flash technology. When
reading from the same device on NetBSD-current with RPi4, I get around 117
MiB/sec, which is pretty good compared to the SD card.
I hate when manufacturers use vague slogans like "Speed up to 130 MB/s".
Yeah, maybe, but only when reading.
You have to be quite careful when buying flash. If they don't spec the write speed, assume it's terrible.
For me, finding suitable fast USB Flash sticks has always been a matter of shop around a lot, and then but the best two or three (likely not the cheapest, but usually < 25% more) and see which one(s) perform well enough and keep those. The ones that do advertise a good write speed generally actually hit it most of the time, at least until the stick gets too worn...
Warner