Date: Tue, 30 Apr 1996 16:23:03 +0530 From: A JOSEPH KOSHY <koshy@india.hp.com> To: hackers@freebsd.org, current@freebsd.org Subject: lmbench IDE anomaly Message-ID: <199604301053.AA141971583@fakir.india.hp.com>
next in thread | raw e-mail | index | archive | help
Running lmdd on a -current system supped around mid apr:
----
>> single lmdd run on scsi disk
krill# lmdd if=/dev/rsd0a of=internal bs=1024 count=8192 # SCSI disk, aha1542
8.00 MB in 11.35 secs, 721.92 KB/sec
>> two simultaneous runs on the scsi disk
krill# lmdd if=/dev/rsd0a of=internal bs=1024 count=8192 &\
lmdd if=/dev/rsd0a of=internal bs=1024 count=8192
8.00 MB in 18.29 secs, 447.80 KB/sec
8.00 MB in 18.32 secs, 447.12 KB/sec
----
The performance degradation per process is around 2x which is to be expected.
The overall throughput is around the same as the single benchmark case.
However when the same exercise is repeated with the IDE disk:
----
krill# lmdd if=/dev/rwd0a of=internal bs=1024 count=8192 # IDE disk
8.00 MB in 9.17 secs, 892.89 KB/sec
krill# lmdd if=/dev/rwd0a of=internal bs=1024 count=8192 &\
lmdd if=/dev/rwd0a of=internal bs=1024 count=8192
8.00 MB in 72.99 secs, 112.24 KB/sec
8.00 MB in 73.02 secs, 112.19 KB/sec
----
Here we see a 8x degradation per process; 4x in terms of total throughput.
Is this to be expected, or am i doing something wrong here? The system was
otherwise idle during these tests.
Koshy
----
System details
----
FreeBSD 2.2-CURRENT #2: Tue Apr 30 08:29:38 IST 1996
root@krill.india.hp.com:/usr/src/sys/compile/KRILL
CPU: Pentium (89.99-MHz 586-class CPU)
Origin = "GenuineIntel" Id = 0x525 Stepping=5
Features=0x1bf<FPU,VME,DE,PSE,TSC,MSR,MCE,CX8>
real memory = 16777216 (16384K bytes)
avail memory = 14733312 (14388K bytes)
Probing for devices on PCI bus 0:
chip0 <generic PCI bridge (vendor=1004 device=0005 subclass=0)> rev 1 on pci0:0
chip1 <generic PCI bridge (vendor=1004 device=0006 subclass=1)> rev 1 on pci0:1
vga0 <VGA-compatible display device> rev 45 int a irq 9 on pci0:5
pci0:7: CMD, device=0x0640, class=storage (ide) int a irq 14 [no driver assigned]
Probing for devices on the ISA bus:
sc0 at 0x60-0x6f irq 1 on motherboard
sc0: VGA color <16 virtual consoles, flags=0x0>
ed0 at 0x2c0-0x2df irq 15 maddr 0xd8000 on isa
ed0: address 08:00:09:a6:a3:9c, type HP-PCLAN+ (32-bit regular IO)
psm0 at 0x60-0x63 irq 12 on motherboard
fdc0 at 0x3f0-0x3f7 irq 6 drq 2 on isa
fdc0: NEC 72065B
fd0: 1.44MB 3.5in
wdc0 at 0x1f0-0x1f7 irq 14 on isa
wdc0: unit 0 (wd0): <QUANTUM MAVERICK 540A>
wd0: 516MB (1057392 sectors), 1049 cyls, 16 heads, 63 S/T, 512 B/S
aha0 at 0x330-0x333 irq 11 drq 5 on isa
(aha0:5:0): "QUANTUM LPS1080S 1220" type 0 fixed SCSI 2
sd0(aha0:5:0): Direct-Access 1001MB (2051460 512 byte sectors)
npx0 on motherboard
npx0: INT 16 interface
----
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199604301053.AA141971583>