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Date:      Sun, 7 Jan 2018 02:44:18 -0800
From:      Mark Millard <markmi@dsl-only.net>
To:        blubee blubeeme <gurenchan@gmail.com>
Cc:        FreeBSD Current <freebsd-current@freebsd.org>
Subject:   Re: USB stack
Message-ID:  <0AB4ED58-E01A-4761-B6EF-4D56F8CA21E3@dsl-only.net>
In-Reply-To: <CALM2mEnaA7zDVfONFQEBtC2WghbRFoFW2iPpmBKohP1pd45CcQ@mail.gmail.com>
References:  <3F9697E3-3C25-45CB-804A-9C3607E434C4@dsl-only.net> <CALM2mEnaA7zDVfONFQEBtC2WghbRFoFW2iPpmBKohP1pd45CcQ@mail.gmail.com>

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[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
>=20
>  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.

=3D=3D=3D
Mark Millard
markmi at dsl-only.net





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