Re: no merit from using DMA-66?
Hello!
Are you really sure you're measuring the maximal bus speed?
Because the bus speed (UDMA33=33MB/sec; UDMA66=66MB/sec) is only the maximum
data rate which can be transferred. However, the magnetic disk can never be
that fast, so that data rates of 16MB/sec are quite normal and not bad.
25MB/sec must be a very good hard disk. So, just don't worry, this high data
rates can only be reached if the data comes from the HDD cache over the bus.
Kind Regards,
Stephan Hachinger
----- Original Message -----
From: Vachirasuk <vachi@pop07.odn.ne.jp>
To: <debian-user@lists.debian.org>
Sent: Saturday, March 18, 2000 4:00 PM
Subject: no merit from using DMA-66?
> Hi all,
>
> Please cc me. I am not subscribing to this list. Thanks :-)
>
> I bought a new harddisk that can do DMA-66 lately(Matrox DiamodMax
> 17GB). However it doesn't look like I get any merit out of it at
> all. I patch the kernel and everything seems to work fine. But hdparm
> -t result is a bit slower than a DMA-33 harddisk I was using(around
> 18MB/sec). I heard somewhere that one should get around 25MB/sec from
> DMA-66. Any idea? I am using potato, BE6 motherboard(HPT366 is DMA-66
> ide controller for ide2 and ide3).
>
> Here is what I did:
>
> 1) patch the kernel(2.2.14) with the infamouse hedrick patch. config:
> CONFIG_BLK_DEV_IDE=y
> # CONFIG_BLK_DEV_HD_IDE is not set
> CONFIG_BLK_DEV_IDEDISK=y
> # CONFIG_IDEDISK_MULTI_MODE is not set
> CONFIG_BLK_DEV_IDECD=y
> # CONFIG_BLK_DEV_IDETAPE is not set
> # CONFIG_BLK_DEV_IDEFLOPPY is not set
> # CONFIG_BLK_DEV_IDESCSI is not set
> CONFIG_BLK_DEV_CMD640=y
> # CONFIG_BLK_DEV_CMD640_ENHANCED is not set
> CONFIG_BLK_DEV_RZ1000=y
> CONFIG_BLK_DEV_IDEPCI=y
> CONFIG_BLK_DEV_IDEDMA=y
> CONFIG_IDEDMA_AUTO=y
> # IDEDMA_NEW_DRIVE_LISTINGS is not set
> IDEDMA_PCI_EXPERIMENTAL=y
> # CONFIG_BLK_DEV_OFFBOARD is not set
> CONFIG_BLK_DEV_HPT366=y
> # HPT366_FAST_IRQ_PREDICTION is not set
> # HPT366_MODE3 is not set
>
> 2) hook the new drive to ide2 so I now have /dev/hda(DMA-33),
> /dev/hde(DMA-66). I have linux root filesystem on /dev/hda2(guess
> what I have on /dev/hda1) and /usr and /home on /dev/hde1 and
> /dev/hde2.
>
> 3) reboot with the new kernel. The boot message follow:
>
> PIIX4: IDE controller on PCI bus 00 dev 39
> PIIX4: not 100% native mode: will probe irqs later
> ide0: BM-DMA at 0xf000-0xf007, BIOS settings: hda:DMA, hdb:pio
> ide1: BM-DMA at 0xf008-0xf00f, BIOS settings: hdc:pio, hdd:pio
> HPT366: onboard version of chipset, pin1=1 pin2=2
> HPT366: IDE controller on PCI bus 00 dev 98
> HPT366: not 100% native mode: will probe irqs later
> ide2: BM-DMA at 0xb800-0xb807, BIOS settings: hde:DMA, hdf:pio
> HPT366: IDE controller on PCI bus 00 dev 99
> HPT366: not 100% native mode: will probe irqs later
> ide3: BM-DMA at 0xc400-0xc407, BIOS settings: hdg:pio, hdh:pio
> hda: QUANTUM FIREBALL CX6.4A, ATA DISK drive
> hdc: ASUS CD-S400/A, ATAPI CDROM drive
> hde: Maxtor 91700U5, ATA DISK drive
> ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
> ide1 at 0x170-0x177,0x376 on irq 15
> ide2 at 0xb000-0xb007,0xb402 on irq 11
> hda: QUANTUM FIREBALL CX6.4A, 6149MB w/418kB Cache, CHS=784/255/63,
UDMA(33)
> hde: Maxtor 91700U5, 16228MB w/2048kB Cache, CHS=32972/16/63, UDMA(66)
> hdc: ATAPI 40X CD-ROM drive, 128kB Cache
>
> 4) do hdparm -t with /dev/hda and /dev/hde I got:
>
> Zero:/root# hdparm -t /dev/hda <---DMA-33
>
> /dev/hda:
> Timing buffered disk reads: 64 MB in 4.04 seconds = 15.84 MB/sec
> Zero:/root# hdparm -t /dev/hde <---DMA-66
>
> /dev/hde:
> Timing buffered disk reads: 64 MB in 9.10 seconds = 7.03 MB/sec
>
> I did this several times and got the same result. WTF it was slower
> than DMA-33!!
>
> 5) I moved root file system to /dev/hde so all linux is in the same
> drive now. rebooted and did hdparm test again. Now I got 18MB/sec
> for both /dev/hda and /dev/hde.
>
> 6) I get another DMA-66 harddisk(Quantum 8GB) from a friend and hook
> it too ide3. Now they all gave 18MB/sec from hdparm test.
>
> 7) HD benchamrk on Win98 tell me that the data transfer rate of
> /dev/hdg is double of /dev/hda(Win can't see /dev/hde coz it has no
> vfat partition), which it should be, had it work correctly.
>
> So, I guess it is a problem of linux and my configuration. Can someone
> help me get this right? Oh, here is harddisk config I got from
> hdparm(both drives have same result)
>
> multcount = 0 (off)
> I/O support = 0 (default 16-bit)
> unmaskirq = 0 (off)
> using_dma = 1 (on)
> keepsettings = 0 (off)
> nowerr = 0 (off)
> readonly = 0 (off)
> readahead = 8 (on)
>
> I did fiddle with multcount, I/O support and unmaskirq but they seem
> to help nothing.
>
> Best Regards,
>
> Vachi
>
> -----
> Vachirasuk Setalaphruk
> ISE, Osaka University
>
>
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