From: Kevin Hui <khui@cs.toronto.edu> To: freebsd-questions@freebsd.org, freebsd-hackers@freebsd.org Subject: Experiencing very slow raw write speeds on /dev/ad1 Message-ID: <Pine.GSO.4.21.0108091853190.5157-100000@gardiner.cs>
next in thread | raw e-mail | index | archive | help
Hi all,
I have installed 2 Maxtor UDMA100 drives in my system, sharing the channel
ide0. /dev/ad0 contains all the FreeBSD partitions and ad1 is used as a
scratch drive (there's nothing on it). Ide1 channel is used for the DVD
drive (which doesn't support UDMA):
ad0: 39083MB <Maxtor 5T040H4> [79408/16/63] at ata0-master UDMA100
ad1: 39083MB <Maxtor 5T040H4> [79408/16/63] at ata0-slave UDMA100
acd0: DVD-ROM <Pioneer DVD-ROM ATAPIModel DVD-116 0109> at ata1-master
using PIO4
Running rawio (available from the Ports collection under benchmarks) on
/dev/ad1 shows the following:
# rawio -p 1 -r /dev/ad1
Random read Sequential read Random write Sequential write
ID K/sec /sec K/sec /sec K/sec /sec K/sec /sec
ad1 36175.1 2208
# rawio -p 1 -w /dev/ad1
Random read Sequential read Random write Sequential write
ID K/sec /sec K/sec /sec K/sec /sec K/sec /sec
ad1 950.1 58
The single-process sequential read time is very good (~36MB/s) but the
single-process sequential write time is terrible (950.1KB/s). Does anyone
have any idea why this is happening?
How complete is the support for UDMA under FreeBSD? I'm using the VIA
82C686 onboard ATA100 controller.
Any information would be appreciated.
-Kevin.
-----------------------
FreeBSD 4.3-RELEASE #0: Sat Apr 21 10:54:49 GMT 2001
jkh@narf.osd.bsdi.com:/usr/src/sys/compile/GENERIC
Timecounter "i8254" frequency 1193182 Hz
CPU: Pentium III/Pentium III Xeon/Celeron (1004.52-MHz 686-class CPU)
Origin = "GenuineIntel" Id = 0x686 Stepping = 6
Features=0x383f9ff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,MMX,FXSR,SSE>
real memory = 268353536 (262064K bytes)
avail memory = 256905216 (250884K bytes)
...
atapci0: <VIA 82C686 ATA100 controller> port 0xb800-0xb80f at device 4.1
on pci0
ata0: at 0x1f0 irq 14 on atapci0
ata1: at 0x170 irq 15 on atapci0
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?Pine.GSO.4.21.0108091853190.5157-100000>