Hello, On Thu, Jan 20, 2005 at 08:00:39PM +0100 or thereabouts, Emanuel Strobl wrote: > > > > I observed a strange behaviour which seems to explain my often noticed > > "16MB/s hard-limit" > > > > I have a UDMA133 drive (MAXTOR 6L060J3) which saturates at 16MB/s when I > > dump anything to it, regardless of the block size. This transfer rate is > > reached with bs=4k and doesn't increase any more even not with bs=64k. > > > > Can anybody confirm that for different hw? Especially people like fandino > > who already discussed poor ata performance on -current (~16 Oct. 04).
my tests shows speeds ranging from 36.9MB/s up to 59.3MB/s.
System is 6.0-CURRENT (yup I know this is -stable list), built on Jan
10, 2005 with VIA 8235 UDMA133 controller.
Disk configuration is as following:
ad0: 38172MB <MAXTOR 6L040J2/AR1.0400> [77557/16/63] at ata0-master
UDMA133
ad1: 39205MB <Maxtor 2F040J0/VAM51JJ0> [79656/16/63] at ata0-slave
UDMA133
/usr is located on /dev/ad0s1e, and /various is located on
/dev/ad1s1d.
Testing of ad0:
pleiades# dd if=/dev/zero of=/usr/testfile bs=4k count=2000
8192000 bytes transferred in 0.161283 secs (50792701 bytes/sec)
pleiades# dd if=/dev/zero of=/usr/testfile bs=16k count=2000
32768000 bytes transferred in 0.792992 secs (41321975 bytes/sec)
pleiades# dd if=/dev/zero of=/usr/testfile bs=64k count=2000
131072000 bytes transferred in 3.386982 secs (38698759 bytes/sec)
Testing for ad1:
pleiades# dd if=/dev/zero of=/various/testfile bs=4k count=2000
8192000 bytes transferred in 0.131618 secs (62240716 bytes/sec)
pleiades# dd if=/dev/zero of=/various/testfile bs=16k count=2000
32768000 bytes transferred in 0.674646 secs (48570665 bytes/sec)
pleiades# dd if=/dev/zero of=/various/testfile bs=64k count=2000
131072000 bytes transferred in 3.184140 secs (41164020 bytes/sec)
I also run these tests on another machine shows speeds ranging from
49MB/s up to 63MB/s. System is 5.3-STABLE built on Dec 7, 2004 with
SiS 735 UDMA100 controller.
Disk configuration is as following:
ad0: 76319MB <WDC WD800JB-00ETA0/77.07W77> [155061/16/63] at
ata0-master UDMA100
/usr is located on /dev/ad0s1e.
Testing of ad0:
amber# dd if=/dev/zero of=/usr/testfile bs=4k count=2000
8192000 bytes transferred in 0.154835 secs (52907939 bytes/sec)
amber# dd if=/dev/zero of=/usr/testfile bs=16k count=2000
32768000 bytes transferred in 0.495422 secs (66141576 bytes/sec)
amber# dd if=/dev/zero of=/usr/testfile bs=64k count=2000
131072000 bytes transferred in 2.546718 secs (51467023 bytes/sec)
I hope that this information will help you.
Cheers,
Martin
--
martin hudec
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