U160 on sym53c8xx very slow

U160 on sym53c8xx very slow

[nico]

Hi,

I have very poor performance with my Ultra160 disks (fujitsu MAN3184MP,
10000rpms).
When I copy a reasonably large (500MB) file from /dev/sda2 to /dev/sda3,
it copies at a rate of 10-20 MB/sec maximum.
I was expecting better troughput.

Here is the result of a dmesg:


----------------------
ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
PCI: Found IRQ 11 for device 0000:00:08.0
PCI: Sharing IRQ 11 with 0000:00:07.2
PCI: Sharing IRQ 11 with 0000:00:07.3
PCI: Sharing IRQ 11 with 0000:00:0b.0
sym0: <1010-33> rev 0x1 at pci 0000:00:08.0 irq 11
sym0: using 64 bit DMA addressing
sym0: Symbios NVRAM, ID 7, Fast-80, SE, parity checking
sym0: open drain IRQ line driver, using on-chip SRAM
sym0: using LOAD/STORE-based firmware.
sym0: handling phase mismatch from SCRIPTS.
sym0: SCAN AT BOOT disabled for targets 0 1 2 3 4 5 8 9 10 11 12 13 14 15.
sym0: SCAN FOR LUNS disabled for targets 0 1 2 3 4 5 6 8 9 10 11 12 13 14 15.
sym0: SCSI BUS has been reset.
scsi0 : sym-2.1.18b
  Vendor: FUJITSU   Model: MAN3184MP         Rev: 0108
  Type:   Direct-Access                      ANSI SCSI revision: 03
sym0:6:0: tagged command queuing enabled, command queue depth 16.
PCI: Found IRQ 15 for device 0000:00:08.1
PCI: Sharing IRQ 15 with 0000:00:0d.0
PCI: Sharing IRQ 15 with 0000:00:0f.0
sym1: <1010-33> rev 0x1 at pci 0000:00:08.1 irq 15
sym1: using 64 bit DMA addressing
sym1: Symbios NVRAM, ID 2, Fast-80, SE, parity checking
sym1: open drain IRQ line driver, using on-chip SRAM
sym1: using LOAD/STORE-based firmware.
sym1: handling phase mismatch from SCRIPTS.
sym1: SCAN AT BOOT disabled for targets 0 1 3 4 5 6 7 8 9 10 11 12 13 14 15.
sym1: SCAN FOR LUNS disabled for targets 0 1 3 4 5 6 7 8 9 10 11 12 13 14 15.
sym1: SCSI BUS has been reset.
sym1: SCSI BUS mode change from SE to SE.
sym1: SCSI BUS has been reset.
scsi1 : sym-2.1.18b
sym0:6:0:M_REJECT to send for : 1-6-4-c-0-3e-1-0.
sym0:6:0:M_REJECT received (7:8).
sym0:6: FAST-20 WIDE SCSI 40.0 MB/s ST (50.0 ns, offset 31)
SCSI device sda: 35885448 512-byte hdwr sectors (18373 MB)
SCSI device sda: drive cache: write back
 sda: sda1 sda2 < sda5 sda6 sda7 sda8 sda9 sda10 sda11 sda12 sda13 >
Attached scsi disk sda at scsi0, channel 0, id 6, lun 0
Attached scsi generic sg0 at scsi0, channel 0, id 6, lun 0,  type 0

----------------------


Something wrong with my configuration? Is it a setting of my adapter
(Tekram DC-390-U3W) that is wrong? Should I plug it on another pci slot?
Else?


Thank you very much for your help.

BTW: it's a 2,6,0-test8 on a debian unstable.

Re: U160 on sym53c8xx very slow

[Matthew Wilcox]

On Mon, Oct 20, 2003 at 03:02:47PM +0200, nico wrote:
> I have very poor performance with my Ultra160 disks (fujitsu MAN3184MP,
> 10000rpms).
> When I copy a reasonably large (500MB) file from /dev/sda2 to /dev/sda3,
> it copies at a rate of 10-20 MB/sec maximum.
> I was expecting better troughput.
> 
> Here is the result of a dmesg:

(Thanks for the dmesg, this is exactly what you needed to report).

> sym0:6: FAST-20 WIDE SCSI 40.0 MB/s ST (50.0 ns, offset 31)

Here's the problem.  For some reason, your 160MB/s disc and 160MB/s
controller have only managed to negotiate 40MB/s between them.

You're copying from sda2 to sda3, so you should get approx half of that
-- 20MB/s which fits with your report (reductions from there would be
due to head seeks and so on).

> Something wrong with my configuration? Is it a setting of my adapter
> (Tekram DC-390-U3W) that is wrong? Should I plug it on another pci slot?
> Else?

I think PCI slot is very unlikely.  Try a shorter SCSI cable, perhaps.

BTW, looking at
http://www.fujitsu.com/support/computing/storage/hdd/eol/ehdd/man3-catalog.html
shows you can only expect a maximum of 40MB/s in your test:

Data transfer rate 	To/from media	52.0 to 84.1 MB/s
			To/from host	160 MB/s

We need to try to figure out why you only get half that though.

-- 
"It's not Hollywood.  War is real, war is primarily not about defeat or
victory, it is about death.  I've seen thousands and thousands of dead bodies.
Do you think I want to have an academic debate on this subject?" -- Robert Fisk

RE: U160 on sym53c8xx very slow

[Tony Battersby]

> sym0: Symbios NVRAM, ID 7, Fast-80, SE, parity checking

SE == Single-ended

You are using a single-ended terminator, which limits the SCSI bus to 40
MB/s bandwidth.  Try a LVD terminator which should give you the full 160
MB/s.  But remember that this only increases the speed at which data can
burst over the SCSI bus, not the speed at which the disk can access the
media.

Anthony J. Battersby
Cybernetics

Re: U160 on sym53c8xx very slow

[nico]

Ok,

Actually I had a problem with a SCA --> 68 pin adapter on another drive on
the same bus (a fuji MAN 3735 MC). This adapter doesn't seem to be lvd,
and thus restarin the bus to operate at 160 MB.

So I plugged it on another SE bus, waiting to buy a new SCA --> 68 pin
adapter, and the MAN 3184 MP is now @ 160.

Thanks for your help.

nico.