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Date:      Tue, 28 Sep 1999 00:51:47 +0200 (MET DST)
From:      Gerard Roudier <groudier@club-internet.fr>
To:        "Kenneth D. Merry" <ken@kdm.org>
Cc:        Kevin Street <street@iname.com>, scsi@FreeBSD.ORG
Subject:   Re: sym driver 0.3.0
Message-ID:  <Pine.LNX.3.95.990928003959.429A-100000@localhost>
In-Reply-To: <199909271956.NAA38933@panzer.kdm.org>

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On Mon, 27 Sep 1999, Kenneth D. Merry wrote:

>              ccd0              da0              da1              da2
>   KB/t tps  MB/s   KB/t tps  MB/s   KB/t tps  MB/s   KB/t tps  MB/s
>   8.00 994  7.76   8.00  49  0.38   8.00 521  4.07   8.00 472  3.69
>   8.00 1010  7.89   0.00   0  0.00   8.00 487  3.81   8.00 523  4.08
>   8.00 1012  7.91   0.00   0  0.00   8.00 489  3.82   8.00 523  4.08

This sym_hipd driver can perform at least 5 times the above number of 8K
transactions per second on 1 LVD BUS given appropriate hard disks (even if
reselections are used). So, such a poor testing is inappropriate for the
sym_hipd driver that would absolutely not be the bottleneck.=20

(Btw, using a 875 the sym_hipd driver should be able to perform about=20
4 times the above Tps given appripriate hard disks)

> Now that's a fair number of transactions per second, and certainly not a
> bad benchmark of drive and controller performance.
>=20
> Later stages of the dump don't go as fast, since they don't necessarily d=
o
> everything in 8K chunks.  Here is sample iostat output from stage 4 of th=
e
> same dump on the same system:
>=20
>             ccd0              da0              da1              da2
>   KB/t tps  MB/s   KB/t tps  MB/s   KB/t tps  MB/s   KB/t tps  MB/s
>   4.66 623  2.84   0.00   0  0.00   4.76 301  1.40   4.58 322  1.44
>   3.85 381  1.43   0.00   0  0.00   3.73 195  0.71   3.97 186  0.72
>   3.99 434  1.69   0.00   0  0.00   3.85 188  0.71   4.10 246  0.98
>   4.32 447  1.88   0.00   0  0.00   4.39 226  0.97   4.24 221  0.91

This one is still inadequate.

> So the transaction counts vary widely, and the average throughput isn't
> all that great for a pair of drives that can otherwise do at least 30MB/s=
ec
> together.  But the number of transactions is still fairly high.
>=20
> I think what you may want to do is ask Kevin to give you some comparisons
> of iostat output from dumps with the ncr driver and dumps with the sym
> driver, so you can compare how many average transactions per second happe=
n
> in each stage of the dump with each driver.  That might shed light on
> whether there are any significant performance differences between the
> drivers.

I will not ask anything, but Kevin can post anything he wants, and I will
reply to him.

G=E9rard.



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