Subject: Re: SCO Xenix w/SCSI Performance Testing/Results 
Distribution: world
Organization: BT
X-Mailer: Simple NEWS 1.90 (ka9q DIS 1.19)
Date: Fri, 1 Jan 1993 16:26:35 +0000

In article <74@consult.UUCP> bob@consult.UUCP writes:

>
>>        OLD MACHINE                             NEW MACHINE
>> 386/33 w/8mb memory 64kcache           486/DX266 w/16mb memory 256k cache
>> Ultrastor 12F ESDI controller          Adaptec 1542 SCSI controller
>> Maxtor 338mb drive (~ 16ms)            HP 667 SCSI-2 drive (~13ms)
>> CMS Enhancement 250mb tape             Archive ST-525 mb tape (SCSI)
>> SCO Xenix 2.3.2                        SCO Xenix 2.3.4 GT
>>                  Tape backup results when using CTAR
>> Typical:  2.3mb/min                    Typical:  5.8mb/min
>> 
>Results:
>                        -----Old System------  -----New System------
>DEVICE BLOCKSIZE COUNT  REALTIME USER  KERNEL  REALTIME USER  KERNEL
>====== ========= =====  ======== ====  ======  ======== ====  ======
>rhd0a     2k     8192    25.4    0.2    5.0      38.8   0.2     1.6  
>hd0a      2k     8192    38.3    0.5   15.1      59.9   0.0    26.7
>rhd0a    256k     64     25.6    0.0    3.8      36.8   0.0     1.3
>hd0a     256k     64     25.6    0.0   12.9      59.6   0.0    26.5
>rroot     2k     8192    26.8    0.3    5.0      38.8   0.1     1.9
>root      2k     8192    34.4    0.5   15.6      59.6   0.1    26.9
>rroot    256k     64     25.9    0.0    3.8      36.9   0.0     1.8
>root     256k     64     25.9    0.0   13.0      59.6   0.0    26.7
>rhd00     2k     8192    25.4    0.5    4.7      38.8   0.1     1.8
>hd00      2k     8192    34.7    0.5   14.5      59.6   0.1    27.0
>rhd00    256k     64     25.7    0.0    3.7      36.9   0.0     1.9
>hd00     256k     64     27.0    0.0   13.1      59.7   0.0    27.0
>

I did some similar tests on 2 SCO Unix 3.2.2 systems. 

         SYSTEM 1                               SYSTEM 2
 486/33 8MB memory 64Kcacke             486/25 8MB memory, no external cache
 Ultrastor 12F ESDI controller          Ultrastor 14F SCSI controller
 Maxtor 338mb drive (~ 16ms)            Quantum 425S FAST SCSI-2 drive (256K
                                        cache)


                        ------SYSTEM 1------   ------SYSTEM 2-------
DEVICE BLOCKSIZE COUNT  REALTIME USER  KERNEL  REALTIME USER  KERNEL
====== ========= =====  ======== ====  ======  ======== ====  ======
rhd0a     2k     8192    25.0    0.2   12.3      40.8   0.6    15.5
hd0a      2k     8192    25.4    0.2   13.4      33.3   0.5    10.9
rhd0a    256k     64     23.8    0.0    7.8      20.3   0.0     4.1
hd0a     256k     64     25.2    0.0   11.5      33.2   0.0     7.8
rroot     2k     8192    25.3    0.2   12.4      42.1   0.6    15.7
root      2k     8192    24.9    0.1   13.1      33.1   0.5    10.8
rroot    256k     64     24.5    0.0    7.3      19.3   0.0     4.3
root     256k     64     25.0    0.0   11.7      35.0   0.0     7.7
rhd00     2k     8192    25.5    0.2   12.0      41.3   0.4    16.1
hd00      2k     8192    24.8    0.1   12.9      34.9   0.4    10.9
rhd00    256k     64     23.9    0.0    7.8      20.1   0.0     4.3
hd00     256k     64     24.8    0.0   11.7      33.3   0.0     7.5
file      2k     8192    23.5    0.1   12.8      18.3   0.5    14.1
file     256k     64     23.5    0.0   11.3      16.3   0.0    10.5

'file' is a large, contiguous file residing on an AFS filesystem. What's
interesting is that REALTIME is always better using AFS than using a disk
device directly, especially for small block sizes. Perhaps AFS has some
inherent lookahead. AFS doesn't seem to impose a measurable overhead
compared to block devices.

On system 2 there seems to be a big overhead for small block sizes whereas on
system 1 block size only seems to make a significant difference on raw
devices.

I did do some informal comparisons between the 14F and 1542B some time ago.
The 14F does appear faster, especially with a FAST SCSI drive (the 1542B
doesn't support FAST).

-----------------------------------------
Lawrence Kirby | fred@genesis.demon.co.uk
Wilts, England | 70734.126@compuserve.com
-----------------------------------------