USB stack

[Mark Millard]

[The following notes a problem with how a test was done.
I omit the rest of the material.]

On 2018-Jan-7, at 2:09 AM, blubee blubeeme <gurenchan at gmail.com> wrote:

. . .
> This is a larger file, not the largest but hey
> 
>  L(q)  ops/s    r/s   kBps   ms/r    w/s   kBps   ms/w    d/s   kBps   ms/d   %busy Name
>     0      4      0      0    0.0      2      8    0.0      0      0    0.0    0.1| nvd0
>     0      0      0      0    0.0      0      0    0.0      0      0    0.0    0.0| md99
>   128    982      1     32   58.8    981 125428  110.5      0      0    0.0  100.0| da1
. . .

Note that almost complete lack of kBps near r/s but the large
kBps near w/s.

It appears that the file has been cached in RAM and is not
being read from media at all. So this test is of a RAM to
disk transfer, not disk to disk, as far as I can tell.

You need to avoid re-reading the same file unless you
dismount and remount between tests or some such. Or
just use a different file not copied since booting (that
file may or may not be a previous copy of the same file
by content).

See if you can get gstat -pd results that show both
read kBps and write kBps figures.

===
Mark Millard
markmi at dsl-only.net