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Date:      Tue, 28 Sep 1999 18:18:19 +0200 (MET DST)
From:      Gerard Roudier <groudier@club-internet.fr>
To:        Kevin Street <street@iname.com>
Cc:        "Kenneth D. Merry" <ken@kdm.org>, scsi@FreeBSD.ORG
Subject:   Re: sym driver 0.3.0
Message-ID:  <Pine.LNX.3.95.990928181444.476A-100000@localhost>
In-Reply-To: <874sgfog96.fsf@mired.eh.local>

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I suggest you to configure the same number of tags for the sym and the ncr
using camcontrol after boot, then to redo your testings and post results.=
=20
You can be sure I will comment them.

G=E9rard.

On 27 Sep 1999, Kevin Street wrote:

> "Kenneth D. Merry" <ken@kdm.org> writes:
> > Gerard Roudier wrote...
> > > You test is not serious. If you only can provide 1.5MB/second through=
put
> > > for a benchmark of SCSI driver, please go away or make comparison wit=
h an
> > > AHA 1542. I consider your posting to be a bad joke and hope that it i=
s not
> > > intentionnaly just bad taste.=20
>=20
> This original hasn't made it to me yet so I don't have all the
> context.  If this comment by Gerard was aimed at me, then my response
> is:  I'm assuming that you intended the sym driver to be used for real
> applications on real machines.  If its only purpose is to run
> benchmarks, then let me know that and I will go away.
>=20
> > I think what you may want to do is ask Kevin to give you some compariso=
ns
> > of iostat output from dumps with the ncr driver and dumps with the sym
> > driver, ...
>=20
> I've done a few more tests.  I tried to see the effect that the
> slow Syquest drive is having.  When I dump to an IDE drive then
> the sym driver is faster than the ncr by 15-20%.  But when I dump
> to the Syquest, then the interference slows down the sym driver more
> than the ncr.  Here's what I got from 8 test runs of dump.
>=20
> dump from da1 to ad0 (IBM SCSI to WD IDE)
> =09time=09KB/sec
> ncr=09246=091764
> ncr=09250=091736
> sym=09211=092056
> sym=09209=092076
>=20
> dump from da1 to da0 (IBM SCSI to Syjet SCSI)
> =09time=09KB/sec
> ncr=09275=091578
> ncr=09277=091566=09
> sym=09335=091295
> sym=09336=091291
>=20
> Looking at iostat shows dump pushing 64KB blocks at the Syquest
> which is almost keeping up.  It gets behind occasionally and
> the da1 transfers stop until da0 catches up.  With the ncr
> driver it looks like this:
>=20
>       tty             da0              da1             cpu
>  tin tout  KB/t tps  MB/s   KB/t tps  MB/s  us ni sy in id
>=20
>    0   30 64.00  24  1.49   4.75 265  1.23   1  0  5  2 92
>    0   30 64.00  25  1.55   4.71 219  1.01   1  0  2  1 97
>    0   30 64.00  23  1.42   0.00   0  0.00   0  0  0  0100
>    0   30 64.00  25  1.55   0.00   0  0.00   0  0  0  0 99
>    0   30 53.92  25  1.30   3.56 275  0.96   1  0  6  1 92
>    0   30 64.00  25  1.55   3.60 564  1.98   0  0 15  2 83
>=20
> On the sym driver, the pauses from da1 are more frequent and
> longer.  On the Syquest at da0, there's something strange
> going on.  The transaction rate on da0 drops way off while it's=20
> trying to catch up, which means that da1 is forced to wait
> longer before it can start blasting data at it again.
>=20
>       tty             da0              da1             cpu
>  tin tout  KB/t tps  MB/s   KB/t tps  MB/s  us ni sy in id
>=20
>    0   30 64.00  22  1.36   2.91 397  1.13   0  0 21 18 60
>    0   30 64.00  21  1.30   3.41 292  0.97   1  0 14 21 64
>    0   30 64.00  20  1.24   3.75  82  0.30   0  0  5 21 74
>    0   30 64.00  21  1.30   0.00   0  0.00   0  0  0 27 72
>    0   30 64.00  21  1.30   0.00   0  0.00   0  0  0 26 73
>    0   30 64.00  19  1.18   0.00   0  0.00   0  0  0 24 75
>    0   89 64.00  17  1.05   0.00   0  0.00   2  0  0 17 81
>    0   30 64.00  15  0.93   0.00   0  0.00   1  0  0 14 85
>    0   30 64.00   8  0.50   0.00   0  0.00   0  0  0  8 92
>    0   30 64.00   8  0.50   0.00   0  0.00   0  0  0  1 99
>    0   30 55.27  22  1.18   3.69 702  2.53   2  0 11  6 82
>    0   30 64.00  22  1.36   3.78 670  2.47   1  0 21 16 62
>    0   30 64.00  23  1.42   3.19 478  1.49   1  0 21 17 61
>    0   30 64.00  20  1.24   0.00   0  0.00   0  0  0 22 77
>    0   30 64.00  17  1.05   0.00   0  0.00   1  0  0 16 83
>    0   30 64.00   8  0.50   0.00   0  0.00   0  0  0  9 91
>    0   30 64.00   4  0.25   0.00   0  0.00   0  0  0  4 96
>    0   30 48.95  21  0.99   3.43 520  1.74   2  0  8  2 88
>=20
> So this would appear to be the cause of the slower dumps.
> Perhaps this is error recovery activity on da0?  Whatever
> it is, the sym driver isn't handling it as gracefully as
> the ncr.
>=20
> --=20
> Kevin Street
> street@iname.com
>=20
>=20
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