Yet another disk transfer speed problem

DISCUSSION Bharath Krishnan 4 participants 6 messages Feb 28, 2002 – Mar 1, 2002

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Bharath Krishnan

author

2002-02-28 16:39 UTC #0 lore raw

Hello!

Please CC: me on replies,

Problem: ata disk on secondary controller of PDC20265 gives sub-par performance.

both disks have c3 and d1 set along with X69.

hdparm -tT /dev/hdg:
/dev/hdg:
Timing buffer-cache reads: 128 MB in 0.77 seconds =166.23 MB/sec
Timing buffered disk reads: 64 MB in 3.81 seconds = 16.80 MB/sec

compared to
hdparm -tT /dev/hde:
/dev/hde:
Timing buffer-cache reads: 128 MB in 0.73 seconds =175.34 MB/sec
Timing buffered disk reads: 64 MB in 1.82 seconds = 35.16 MB/sec

Setup:
kernel: 2.4.17
pdc20265 controller on asus a7v motherboard. kernel config options:
CONFIG_BLK_DEV_PDC202XX=y CONFIG_PDC202XX_BURST=y
# CONFIG_PDC202XX_FORCE is not set
# CONFIG_BLK_DEV_ATARAID_PDC is not set

similar behavior with redhat 7.2 updated kernel 2.4.9-21

hde: IBM-DTLA-307015, ATA DISK drive
hdg: MAXTOR 6L040J2, ATA DISK drive

Interesting stuff from dmesg:
ide2: BM-DMA at 0x8000-0x8007, BIOS settings: hde:DMA, hdf:pio
ide3: BM-DMA at 0x8008-0x800f, BIOS settings: hdg:DMA, hdh:pio

cat /proc/ide/ide2/config
pci bus 00 device 88 vid 105a did 0d30 channel 0 5a 10 30 0d 07 00 10 02 02 00 80 01 00 20 00 00 01 94 00 00 01 90 00 00 01 88 00 00 01 84 00 00 01 80 00 00 00 00 00 d4 00 00 00 00 5a 10 33 4d 00 00 00 00 58 00 00 00 00 00 00 00 0a 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 be 33 00 00 00 00 00 00 01 00 01 00 00 00 00 00 f1 24 41 00 c4 f3 4f 00 f1 24 41 00 c4 f3 4f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

cat /proc/ide/ide3/config
pci bus 00 device 88 vid 105a did 0d30 channel 1 5a 10 30 0d 07 00 10 02 02 00 80 01 00 20 00 00 01 94 00 00 01 90 00 00 01 88 00 00 01 84 00 00 01 80 00 00 00 00 00 d4 00 00 00 00 5a 10 33 4d 00 00 00 00 58 00 00 00 00 00 00 00 0a 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 be 33 00 00 00 00 00 00 01 00 01 00 00 00 00 00 f1 24 41 00 c4 f3 4f 00 f1 24 41 00 c4 f3 4f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

hdparm -i
/dev/hde
Model=IBM-DTLA-307015, FwRev=TX2OA50C, SerialNo=YF0YFFX4393
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs } RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=40 BuffType=DualPortCache, BuffSize=1916kB, MaxMultSect=16, MultSect=16 CurCHS=16383/16/63, CurSects=-66060037, LBA=yes, LBAsects=30003120 IORDY=on/off, tPIO={min:240,w/IORDY:120}, tDMA={min:120,rec:120} PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 *udma5 AdvancedPM=yes: disabled (255)
Drive Supports : ATA/ATAPI-5 T13 1321D revision 1 : ATA-2 ATA-3 ATA-4
ATA-5

/dev/hdg
Model=MAXTOR 6L040J2, FwRev=A93.0300, SerialNo=662125114610
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs } RawCHS=16383/16/63, TrkSize=32256, SectSize=21298, ECCbytes=4 BuffType=DualPortCache, BuffSize=1820kB, MaxMultSect=16, MultSect=16 CurCHS=16383/16/63, CurSects=-66060037, LBA=yes, LBAsects=78177792 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120} PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 *udma5 udma6 AdvancedPM=no
Drive Supports : ATA/ATAPI-5 T13 1321D revision 1 : ATA-1 ATA-2 ATA-3
ATA-4 ATA-5

cat /proc/ide/pdc202xx

                               PDC20265 Chipset.
------------------------------- General Status
---------------------------------Burst Mode                           :
enabled
Host Mode                            : Normal
Bus Clocking                         : 33 PCI Internal
IO pad select                        : 10 mA
Status Polling Period                : 8

Interrupt Check Status Polling Delay : 11
--------------- Primary Channel ---------------- Secondary Channel ----
enabled enabled
66 Clocking enabled enabled
Mode PCI Mode PCI
FIFO Empty FIFO Empty
--------------- drive0 --------- drive1 -------- drive0 ----------
drive1 -DMA enabled: yes no
yes no
DMA Mode: UDMA 4 NOTSET UDMA 4
NOTSET
PIO Mode: PIO 4 NOTSET PIO 4
NOTSET

What is going on? I do have ata100 cables.

Thanks,

-bharath

Joseph Malicki

2002-02-28 20:06 UTC #1 lore raw

Have you considered that perhaps one of your drives is just faster than the other?
This happens.

-joe

----- Original Message -----
From: "Bharath Krishnan" <[email protected]>
To: <[email protected]>
Sent: Thursday, February 28, 2002 11:34 AM
Subject: Yet another disk transfer speed problem

Quoted 139 lines

Hello!
Please CC: me on replies,
Problem: ata disk on secondary controller of PDC20265 gives sub-par performance.
both disks have c3 and d1 set along with X69.
hdparm -tT /dev/hdg:
/dev/hdg:
Timing buffer-cache reads: 128 MB in 0.77 seconds =166.23 MB/sec
Timing buffered disk reads: 64 MB in 3.81 seconds = 16.80 MB/sec
compared to
hdparm -tT /dev/hde:
/dev/hde:
Timing buffer-cache reads: 128 MB in 0.73 seconds =175.34 MB/sec
Timing buffered disk reads: 64 MB in 1.82 seconds = 35.16 MB/sec
Setup:
kernel: 2.4.17
pdc20265 controller on asus a7v motherboard. kernel config options:
CONFIG_BLK_DEV_PDC202XX=y CONFIG_PDC202XX_BURST=y
# CONFIG_PDC202XX_FORCE is not set
# CONFIG_BLK_DEV_ATARAID_PDC is not set
similar behavior with redhat 7.2 updated kernel 2.4.9-21
hde: IBM-DTLA-307015, ATA DISK drive
hdg: MAXTOR 6L040J2, ATA DISK drive
Interesting stuff from dmesg:
ide2: BM-DMA at 0x8000-0x8007, BIOS settings: hde:DMA, hdf:pio
ide3: BM-DMA at 0x8008-0x800f, BIOS settings: hdg:DMA, hdh:pio
cat /proc/ide/ide2/config
pci bus 00 device 88 vid 105a did 0d30 channel 0 5a 10 30 0d 07 00 10 02 02 00 80 01 00 20 00 00 01 94 00 00 01 90 00 00 01 88 00 00 01 84 00 00 01 80 00 00 00 00 00 d4 00 00 00 00 5a 10 33 4d 00 00 00 00 58 00 00 00 00 00 00 00 0a 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 be 33 00 00 00 00 00 00 01 00 01 00 00 00 00 00 f1 24 41 00 c4 f3 4f 00 f1 24 41 00 c4 f3 4f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
cat /proc/ide/ide3/config
pci bus 00 device 88 vid 105a did 0d30 channel 1 5a 10 30 0d 07 00 10 02 02 00 80 01 00 20 00 00 01 94 00 00 01 90 00 00 01 88 00 00 01 84 00 00 01 80 00 00 00 00 00 d4 00 00 00 00 5a 10 33 4d 00 00 00 00 58 00 00 00 00 00 00 00 0a 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 be 33 00 00 00 00 00 00 01 00 01 00 00 00 00 00 f1 24 41 00 c4 f3 4f 00 f1 24 41 00 c4 f3 4f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
hdparm -i
/dev/hde
Model=IBM-DTLA-307015, FwRev=TX2OA50C, SerialNo=YF0YFFX4393
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs } RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=40 BuffType=DualPortCache, BuffSize=1916kB, MaxMultSect=16, MultSect=16 CurCHS=16383/16/63, CurSects=-66060037, LBA=yes, LBAsects=30003120 IORDY=on/off, tPIO={min:240,w/IORDY:120}, tDMA={min:120,rec:120} PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 *udma5 AdvancedPM=yes: disabled (255)
Drive Supports : ATA/ATAPI-5 T13 1321D revision 1 : ATA-2 ATA-3 ATA-4
ATA-5
/dev/hdg
Model=MAXTOR 6L040J2, FwRev=A93.0300, SerialNo=662125114610
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs } RawCHS=16383/16/63, TrkSize=32256, SectSize=21298, ECCbytes=4 BuffType=DualPortCache, BuffSize=1820kB, MaxMultSect=16, MultSect=16 CurCHS=16383/16/63, CurSects=-66060037, LBA=yes, LBAsects=78177792 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120} PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 *udma5 udma6 AdvancedPM=no
Drive Supports : ATA/ATAPI-5 T13 1321D revision 1 : ATA-1 ATA-2 ATA-3
ATA-4 ATA-5
cat /proc/ide/pdc202xx
                               PDC20265 Chipset.
------------------------------- General Status
---------------------------------Burst Mode                           :
enabled
Host Mode                            : Normal
Bus Clocking                         : 33 PCI Internal
IO pad select                        : 10 mA
Status Polling Period                : 8
Interrupt Check Status Polling Delay : 11
--------------- Primary Channel ---------------- Secondary Channel ----
enabled enabled
66 Clocking enabled enabled
Mode PCI Mode PCI
FIFO Empty FIFO Empty
--------------- drive0 --------- drive1 -------- drive0 ----------
drive1 -DMA enabled: yes no
yes no
DMA Mode: UDMA 4 NOTSET UDMA 4
NOTSET
PIO Mode: PIO 4 NOTSET PIO 4
NOTSET
What is going on? I do have ata100 cables.
Thanks,
(quoted diff) +0 -2
-bharath
-
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Bharath Krishnan

author

2002-02-28 20:09 UTC #2 lore raw

Hi,

I would expect the disk which acts slower(maxtor) to be atleast as fast as the other one (ibm).

reasons:

1. Both are 7200RPM
2. The slower one(maxtor hdg) is one of the newer ata133 disks while that faster one is ata100(ibm hde). I would expect atleast equal performance from both.

Thanks,

-bharath

Quoted 153 lines · Joseph Malicki

Have you considered that perhaps one of your drives is just faster than the other?
This happens.
-joe
----- Original Message -----
From: "Bharath Krishnan" <[email protected]>
To: <[email protected]>
Sent: Thursday, February 28, 2002 11:34 AM
Subject: Yet another disk transfer speed problem
Quoted 139 lines
Hello!
Please CC: me on replies,
Problem: ata disk on secondary controller of PDC20265 gives sub-par performance.
both disks have c3 and d1 set along with X69.
hdparm -tT /dev/hdg:
/dev/hdg:
Timing buffer-cache reads: 128 MB in 0.77 seconds =166.23 MB/sec
Timing buffered disk reads: 64 MB in 3.81 seconds = 16.80 MB/sec
compared to
hdparm -tT /dev/hde:
/dev/hde:
Timing buffer-cache reads: 128 MB in 0.73 seconds =175.34 MB/sec
Timing buffered disk reads: 64 MB in 1.82 seconds = 35.16 MB/sec
Setup:
kernel: 2.4.17
pdc20265 controller on asus a7v motherboard. kernel config options:
CONFIG_BLK_DEV_PDC202XX=y CONFIG_PDC202XX_BURST=y
# CONFIG_PDC202XX_FORCE is not set
# CONFIG_BLK_DEV_ATARAID_PDC is not set
similar behavior with redhat 7.2 updated kernel 2.4.9-21
hde: IBM-DTLA-307015, ATA DISK drive
hdg: MAXTOR 6L040J2, ATA DISK drive
Interesting stuff from dmesg:
ide2: BM-DMA at 0x8000-0x8007, BIOS settings: hde:DMA, hdf:pio
ide3: BM-DMA at 0x8008-0x800f, BIOS settings: hdg:DMA, hdh:pio
cat /proc/ide/ide2/config
pci bus 00 device 88 vid 105a did 0d30 channel 0 5a 10 30 0d 07 00 10 02 02 00 80 01 00 20 00 00 01 94 00 00 01 90 00 00 01 88 00 00 01 84 00 00 01 80 00 00 00 00 00 d4 00 00 00 00 5a 10 33 4d 00 00 00 00 58 00 00 00 00 00 00 00 0a 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 be 33 00 00 00 00 00 00 01 00 01 00 00 00 00 00 f1 24 41 00 c4 f3 4f 00 f1 24 41 00 c4 f3 4f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
cat /proc/ide/ide3/config
pci bus 00 device 88 vid 105a did 0d30 channel 1 5a 10 30 0d 07 00 10 02 02 00 80 01 00 20 00 00 01 94 00 00 01 90 00 00 01 88 00 00 01 84 00 00 01 80 00 00 00 00 00 d4 00 00 00 00 5a 10 33 4d 00 00 00 00 58 00 00 00 00 00 00 00 0a 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 be 33 00 00 00 00 00 00 01 00 01 00 00 00 00 00 f1 24 41 00 c4 f3 4f 00 f1 24 41 00 c4 f3 4f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
hdparm -i
/dev/hde
Model=IBM-DTLA-307015, FwRev=TX2OA50C, SerialNo=YF0YFFX4393
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs } RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=40 BuffType=DualPortCache, BuffSize=1916kB, MaxMultSect=16, MultSect=16 CurCHS=16383/16/63, CurSects=-66060037, LBA=yes, LBAsects=30003120 IORDY=on/off, tPIO={min:240,w/IORDY:120}, tDMA={min:120,rec:120} PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 *udma5 AdvancedPM=yes: disabled (255)
Drive Supports : ATA/ATAPI-5 T13 1321D revision 1 : ATA-2 ATA-3 ATA-4
ATA-5
/dev/hdg
Model=MAXTOR 6L040J2, FwRev=A93.0300, SerialNo=662125114610
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs } RawCHS=16383/16/63, TrkSize=32256, SectSize=21298, ECCbytes=4 BuffType=DualPortCache, BuffSize=1820kB, MaxMultSect=16, MultSect=16 CurCHS=16383/16/63, CurSects=-66060037, LBA=yes, LBAsects=78177792 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120} PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 *udma5 udma6 AdvancedPM=no
Drive Supports : ATA/ATAPI-5 T13 1321D revision 1 : ATA-1 ATA-2 ATA-3
ATA-4 ATA-5
cat /proc/ide/pdc202xx
                               PDC20265 Chipset.
------------------------------- General Status
---------------------------------Burst Mode                           :
enabled
Host Mode                            : Normal
Bus Clocking                         : 33 PCI Internal
IO pad select                        : 10 mA
Status Polling Period                : 8
Interrupt Check Status Polling Delay : 11
--------------- Primary Channel ---------------- Secondary Channel ----
enabled enabled
66 Clocking enabled enabled
Mode PCI Mode PCI
FIFO Empty FIFO Empty
--------------- drive0 --------- drive1 -------- drive0 ----------
drive1 -DMA enabled: yes no
yes no
DMA Mode: UDMA 4 NOTSET UDMA 4
NOTSET
PIO Mode: PIO 4 NOTSET PIO 4
NOTSET
What is going on? I do have ata100 cables.
Thanks,
(quoted diff) +0 -2
-bharath
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

Helge Hafting

2002-03-01 09:07 UTC #3 lore raw

In reply to Bharath Krishnan

Quoted 9 lines · Bharath Krishnan

Hi,
I would expect the disk which acts slower(maxtor) to be atleast as fast as the other one (ibm).
reasons:
1. Both are 7200RPM

Not enough to get anywhere near equal performance.
This also depends on how densely data is packed onto a single track. A 7200 RPM drive reads a whole track in 1/7200 minute, or 1/120 second. That limits the maximum speed - but how much data is there on a single track? Slow 7200 RPM drives have many tracks and little data on each track. Fast drives have fewer tracks and more data in each. Note that this has nothing to do with disk geometry reported by hdparm, that geometry is just a lie.
All new drives have a varying amount of data per track as the outermost tracks are longer than the innermost.
That of course also means the speed varies a lot depending on _what_ track is used for testing.

My atlas IV scsi drive does 21MB/s on the outer tracks and 15MB/s on the inner tracks according to specs. Running bonnie tests on partitions at either end of the drive confirms the difference.

So, expect 7200 RPM drives from different manufacturers to have very different transfer speeds. Or even different sized drives from the same.

Quoted 3 lines

2. The slower one(maxtor hdg) is one of the newer ata133 disks while that faster one is ata100(ibm hde). I would expect atleast equal performance from both.

133 or 100 sets an upper limit of 133 or 100MB/s for sure, but that doesn't matter _at all_ because the platters aren't that fast anyway. The best you'll ever get depends on how much data they fit on the outermost track. The 133 interface will be 33% faster when transferring small amounts of data to or from the drive's internal cache, but it won't impact transfers bigger than the cacee size at all. hdparms 64M test is bigger than the drive's internal cache which probably is a few megs only.

Helge Hafting

Bharath Krishnan

author

2002-03-01 19:52 UTC #4 lore raw

Hi,

I may have been overly simplistic/ignorant in my reasoning.

But, in this case, the slow disk is rated pretty high in performance. It can supposedly do 40MB/sec. Maxtor sells it as D740X, their performance range.

Thanks,

-bharath

Quoted 45 lines · Helge Hafting

Quoted 9 lines · Bharath Krishnan
Hi,
I would expect the disk which acts slower(maxtor) to be atleast as fast as the other one (ibm).
reasons:
1. Both are 7200RPM
Not enough to get anywhere near equal performance.
This also depends on how densely data is packed onto a single track. A 7200 RPM drive reads a whole track in 1/7200 minute, or 1/120 second. That limits the maximum speed - but how much data is there on a single track? Slow 7200 RPM drives have many tracks and little data on each track. Fast drives have fewer tracks and more data in each. Note that this has nothing to do with disk geometry reported by hdparm, that geometry is just a lie.
All new drives have a varying amount of data per track as the outermost tracks are longer than the innermost.
That of course also means the speed varies a lot depending on _what_ track is used for testing.
My atlas IV scsi drive does 21MB/s on the outer tracks and 15MB/s on the inner tracks according to specs. Running bonnie tests on partitions at either end of the drive confirms the difference.
So, expect 7200 RPM drives from different manufacturers to have very different transfer speeds. Or even different sized drives from the same.
Quoted 3 lines
2. The slower one(maxtor hdg) is one of the newer ata133 disks while that faster one is ata100(ibm hde). I would expect atleast equal performance from both.
133 or 100 sets an upper limit of 133 or 100MB/s for sure, but that doesn't matter _at all_ because the platters aren't that fast anyway. The best you'll ever get depends on how much data they fit on the outermost track. The 133 interface will be 33% faster when transferring small amounts of data to or from the drive's internal cache, but it won't impact transfers bigger than the cacee size at all. hdparms 64M test is bigger than the drive's internal cache which probably is a few megs only.

Quoted 2 lines

Helge Hafting

-bharath

Holger Lubitz

2002-03-01 15:59 UTC #5 lore raw

In reply to Bharath Krishnan

Bharath Krishnan proclaimed:

Quoted 5 lines

Hi,
I would expect the disk which acts slower(maxtor) to be atleast as fast as the other one (ibm).

Could you provide fdisk -l for both? For some odd reason unknown to me some filesystems give slower results with hdparm than others, even with the buffer-cache reads (which are intended to measure memory speed, not drive speed, and thus should be the same for all drives on a given mainboard). Also, hdparm directly on the drive device is often a bit slower than hdparm for the first (outermost) partition. These problems have been far worse in older kernels, though. With 2.2 I once benchmarked a vfat-partition at half the speed the same partition gave as ext2.

Holger