low SCSI performance, slightly OT (AMI MegaRAID, Seagate Barracuda)

Jim Duchek (jimduchek@ou.edu)
Wed, 08 Sep 1999 02:17:34 -0500


Hi. I've got a ST15150W 4.3G Seagate Barracuda in my system. It's
fast/wide. My SCSI card is an AMI MegaRAID 418 card. According to a
util called scsiinfo, synchronous transfers are on, and it is
tranferring 16 bits (wide). It's just replaced a Quantum Fireball,
UDMA/33 drive. While things are slightly snappier when the system load
is high (like when X is coming up), on a regular basis things appear to
take much longer. As an example, off hand:

/dev/hda:
Timing buffered disk reads: 64 MB in 6.15 seconds =10.41 MB/sec

/dev/sda:
Timing buffered disk reads: 64 MB in 13.64 seconds = 4.69 MB/sec

And another:

time tar -xzf /home/jrduchek/X335src-1.tgz
6.910u 4.760s 0:24.70 47.2% 0+0k 0+0io
4486pf+0w IDE

time tar -xzf /home/jrduchek/X335src-1.tgz
6.600u 3.910s 0:31.58 33.2% 0+0k 0+0io
4480pf+0w SCSI

The system is a K6-III 450, 192M of RAM, the SCSI card has 4M cache on
it.

Any ideas? Who should I email about questions on the driver, I imagine
AMI themselves will tell me they don't officially support it. Am I
missing something?

Thanks in advance. PS the following is information that might be of
use.

from /proc/pci: Bus 0, device 9, function 0:
Unknown mass storage controller: Unknown vendor Unknown device (rev
3).
Vendor id=101e. Device id=9010.
Medium devsel. IRQ 10. Master Capable. Latency=64.
I/O at 0xec00 [0xec01].

from scsiinfo
[jrduchek@joe megaraid]# scsiinfo -a /dev/sda
Scsiinfo version 1.7(eowmob)

Inquiry command
---------------
Relative Address 0
Wide bus 32 0
Wide bus 16 1
Synchronous neg. 1
Linked Commands 0
Command Queueing 1
SftRe 0
Device Type 0
Peripheral Qualifier 0
Removable? 0
Device Type Modifier 0
ISO Version 0
ECMA Version 0
ANSI Version 2
AENC 0
TrmIOP 0
Response Data Format 0
Vendor: MegaRAID
Product: LD0 RAID0 4094R
Revision level: M.73

Serial Number ''
Data from Rigid Disk Drive Geometry Page
----------------------------------------
Number of cylinders 0
Number of heads 0
Starting write precomp 0
Starting reduced current 0
Drive step rate 0
Landing Zone Cylinder 0
RPL 0
Rotational Offset 0
Rotational Rate 0

Data from Caching Page
----------------------
Write Cache 0
Read Cache 1
Prefetch units 0
Demand Read Retention Priority 0
Demand Write Retention Priority 0
Disable Pre-fetch Transfer Length 0
Minimum Pre-fetch 0
Maximum Pre-fetch 0
Maximum Pre-fetch Ceiling 0

Data from Format Device Page
----------------------------
Removable Medium 0
Supports Hard Sectoring 0
Supports Soft Sectoring 0
Addresses assigned by surface 0
Tracks per Zone 0
Alternate sectors per zone 0
Alternate tracks per zone 0
Alternate tracks per lun 0
Sectors per track 0
Bytes per sector 0
Interleave 0
Track skew factor 0
Cylinder skew factor 0

Data from Error Recovery Page
-----------------------------
AWRE 0
ARRE 0
TB 0
RC 0
EER 0
PER 0
DTE 0
DCR 0
Read Retry Count 0
Correction Span 0
Head Offset Count 0
Data Strobe Offset Count 0
Write Retry Count 0
Recovery Time Limit 0

Data from Control Page
----------------------
RLEC 0
QErr 0
DQue 0
EECA 0
RAENP 0
UUAENP 0
EAENP 0
Queue Algorithm Modifier 0
Ready AEN Holdoff Period 0

Data from Disconnect-Reconnect Page
-----------------------------------
Buffer full ratio 0
Buffer empty ratio 0
Bus Inactivity Limit 0
Disconnect Time Limit 0
Connect Time Limit 0
Maximum Burst Size 0
DTDC 0x0

Data from Defect Lists
----------------------
Unable to read manufacturer defect data.
Unable to read grown defect data.
Data from Notch Parameters Page
-------------------------------
Notched Drive 0
Logical or Physical Notch 0
Max # of notches 0
Active Notch 0
Starting Boundary 0x0
Ending Boundary 0x0
Pages Notched 00000000 00000000

Data from Verify Error Recovery Page
------------------------------------
EER 0
PER 0
DTE 0
DCR 0
Verify Retry Count 0
Verify Correction Span (bits) 0
Verify Recovery Time Limit (ms) 0

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