On 11/30/05, art <[email protected]> wrote:
> Re: SCSI adaptec 19160 speed - 2.6.14-rt13 - Q for scsi experts
>
> On Tue, Nov 29, 2005 at 07:36:44PM -0600, art wrote:
[snip]
> > >
> > > # hdparm -tT /dev/sdb
> > > /dev/sdb:
> > > Timing cached reads: 2316 MB in 2.00 seconds = 1157.90 MB/sec
> > > Timing buffered disk reads: 268 MB in 3.00 seconds = 89.26 MB/sec
> > > # hdparm -tT /dev/sdc
> > >
> > > /dev/sdc:
> > > Timing cached reads: 2512 MB in 2.00 seconds = 1255.49 MB/sec
> > > Timing buffered disk reads: 268 MB in 3.00 seconds = 89.32 MB/sec
> > >
> > > # hdparm -tT /dev/sdb & hdparm -tT /dev/sdc &
> > > [1] 3314
> > > [2] 3315
> > >
> > > /dev/sdb:
> > > /dev/sdc:
> > > Timing cached reads: Timing cached reads: 1228 MB in 2.00 seconds = 613.88 MB/sec
> > > 1316 MB in 1.99 seconds = 659.73 MB/sec
> > > Timing buffered disk reads: Timing buffered disk reads:
> > > 174 MB in 3.00 seconds = 57.91 MB/sec
> > > 170 MB in 3.05 seconds = 55.75 MB/sec
> > > ------------------------------------------------------------------------------------------
> > >
> > > pci is 66Mhz theoretical throuhput ~ 250MB/s
>
> And pci at 33mhz can do 130MB/s or so. With a bit over overhead those
> numbers sure look awful close to what a 33mhz pci bus can handle.
>
> > > controller adaptec asc-19160
> > > discs are 146GB-15krpm-cheetah
> > >
> > > one disc transfer 89MB/s
> > >
> > > adaptec speed with 2 disc on one channel = 57.91+55.75 = 113.66MB/s
> > >
> > > 71% of 160MB/s channel speed i expected ~90%
> > >
> > > any clue?
>
> PCI bus not at 66mhz perhaps? Is it an add in card on onboard? I
> wonder if a pci bus that supports 66mhz has to drop everything to 33mhz
> if any of the cards installed are 33mhz only. Having never tried I
> don't know.
>
> Len Sorensen
>
> --------------------------------------------------------------
> --------------------------------------------------------------
>
> # /sbin/lspci -v
>
> 02:00.0 SCSI storage controller: Adaptec AIC-7892B U160/m (rev 02)
> Subsystem: Adaptec 19160 Ultra160 SCSI Controller
> Flags: bus master, 66Mhz, medium devsel, latency 32, IRQ 16
> BIST result: 00
> I/O ports at a000 [disabled] [size=256]
> Memory at e302a000 (64-bit, non-prefetchable) [size=4K]
> [virtual] Expansion ROM at 50000000 [disabled] [size=128K]
> Capabilities: [dc] Power Management version 2
>
> 02:02.2 USB Controller: NEC Corporation USB 2.0 (rev 04) (prog-if 20 [EHCI])
> Subsystem: Belkin Root Hub
> Flags: bus master, medium devsel, latency 32, IRQ 16
> Memory at e3028000 (32-bit, non-prefetchable) [size=256]
> Capabilities: [40] Power Management version 2
>
> 02:04.0 FireWire (IEEE 1394): Texas Instruments TSB43AB23 IEEE-1394a-2000 Controller (PHY/Link) (prog-if 10 [OHCI])
> Subsystem: Adaptec: Unknown device 0030
> Flags: bus master, medium devsel, latency 32, IRQ 16
> Memory at e302b000 (32-bit, non-prefetchable) [size=2K]
> Memory at e3020000 (32-bit, non-prefetchable) [size=16K]
> Capabilities: [44] Power Management version 2
>
>
> 3 cards on same 16-int Adaptec 19160 at 66Mhz
> but---33Mhz ieee1394a ---- subsystem: Adaptec ???
>
Hmm, seeing your mail got me thinking about how my own disks perform
# lspci -v
00:0b.0 SCSI storage controller: Adaptec AIC-7892A U160/m (rev 02)
Subsystem: Adaptec 29160N Ultra160 SCSI Controller
Flags: bus master, 66Mhz, medium devsel, latency 32, IRQ 5
BIST result: 00
I/O ports at 9800 [disabled] [size=256]
Memory at e3000000 (64-bit, non-prefetchable) [size=4K]
Expansion ROM at 30000000 [disabled] [size=128K]
Capabilities: [dc] Power Management version 2
about the disk (10K RPM IBM UltraStar) from dmesg :
[ 43.387178] Vendor: IBM Model: DDYS-T36950N Rev: S96H
[ 43.406176] Type: Direct-Access ANSI SCSI
revision: 03
[ 43.424651] scsi0:A:6:0: Tagged Queuing enabled. Depth 200
[ 43.442952] target0:0:6: Beginning Domain Validation
[ 43.464011] target0:0:6: wide asynchronous.
[ 43.486866] target0:0:6: FAST-80 WIDE SCSI 160.0 MB/s DT (12.5 ns,
offset 63)
[ 43.514788] target0:0:6: Ending Domain Validation
[ 45.584696] SCSI device sda: 71687340 512-byte hdwr sectors (36704 MB)
[ 45.604490] SCSI device sda: drive cache: write back
[ 45.623781] SCSI device sda: 71687340 512-byte hdwr sectors (36704 MB)
[ 45.643575] SCSI device sda: drive cache: write back
[ 45.661953] sda: sda1 sda2 sda3 sda4
[ 45.691968] sd 0:0:6:0: Attached scsi disk sda
# hdparm -tT /dev/sda
/dev/sda:
Timing cached reads: 904 MB in 2.00 seconds = 451.17 MB/sec
Timing buffered disk reads: 84 MB in 3.05 seconds = 27.52 MB/sec
Not exactely impressive numbers here...
--
Jesper Juhl <[email protected]>
Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html
Plain text mails only, please http://www.expita.com/nomime.html
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