Date: Mon, 24 Feb 1997 15:28:01 -0600 From: bdodson@beowulf.utmb.edu (M. L. Dodson) To: freebsd-questions@freebsd.org Subject: Adding memory slows down 486 to less than 386SX! Message-ID: <199702242128.PAA08444@beowulf.utmb.EDU>
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Hello,
I just upgraded a 486DX-25 from 8MB to 20MB memory and sequential
character disk I/O to a SCSI disk is now slower than to an IDE disk
on a 386SX!
The machine "feels" slow, also. Not only under FreeBSD, but also under
Win95 (for processes that do not cause swapping). I have included bonnie
results below. The 486 has a VLB BusLogic 445C bus mastering SCSI
controller, the 386SX a normal IDE builtin. Note that the 486 is 4-5X
faster for block I/O, which is what I was expecting for everything. The
kernels do not have bounce buffers enabled. Both machines were lightly
loaded. The 486 is a NFS server, the 386SX is a NFS client (it will
eventually be a router for my home network, but ppp was not running
during these benchmarks). Nothing was NFS mounted.
The BIOS setup for the 486 is standard as far as I can tell: 2-1-1-1
memory timing, 256KB cache was enabled, no cache waitstates. The 386
was box stock, also, as far as I know. I have no documentation on
the 386 builtin controller, but BSD probes it as a standard IDE
controller.
I don't get any memory fault indications.
Note that the 386SX is only running a 10MB bonnie file, whereas the 486
was running a 30MB. But I am talking sequential input/output, per
character, rates: 82K/sec vs 55K/sec output and 87K/sec vs 64K/sec for
input.
And why is CPU utilization so high for the block I/O on the 486
relative to the 386SX?
Any help would be appreciated. I'm at a loss.
Bud Dodson
Specific info:
Representative bonnie benchmark results:
16MHz 386SX, 6MB, 120MB IDE (slow) disk:
File './Bonnie.159', size: 10485760
.
.
.
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
10 82 83.2 433 30.1 239 22.5 87 86.3 497 22.5 26.5 14.0
25MHz 486DX, 20MB, 500MB SCSI2 (reasonably quick) disk (BusLogic 445C VLB
busmastering controller):
File './Bonnie.210', size: 31457280
.
.
.
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
30 55 97.7 1818 92.8 1055 73.5 64 98.9 1913 63.6 58.4 16.8
dmesg output for the 486DX:
FreeBSD 2.1.5-RELEASE #0: Wed Sep 4 19:55:48 CDT 1996
root@nagling.611.chedworth.hou.tx.us:/usr/src/sys/compile/NAGLING
CPU: i486DX (486-class CPU)
real memory = 20971520 (20480K bytes)
avail memory = 19075072 (18628K bytes)
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 0x240-0x25f irq 10 on isa
ed0: address 00:40:05:26:19:c4, type NE2000 (16 bit)
sio0 at 0x3f8-0x3ff irq 4 on isa
sio0: type 16450
sio1 at 0x2f8-0x2ff irq 3 on isa
sio1: type 16450
lpt0 at 0x378-0x37f irq 7 on isa
lpt0: Interrupt-driven port
lp0: TCP/IP capable interface
fdc0 at 0x3f0-0x3f7 irq 6 drq 2 on isa
fdc0: NEC 765
fd0: 1.44MB 3.5in
ft0: IOMega tape
wdc0 at 0x1f0-0x1f7 irq 14 on isa
wdc0: unit 0 (wd0): <WDC AC2340H>
wd0: 325MB (666600 sectors), 1010 cyls, 12 heads, 55 S/T, 512 B/S
bt0: Bt44xC/ 0-(32bit) bus
bt0: reading board settings, busmastering, int=11
bt0: version 4.21, sync, parity, 32 mbxs, 32 ccbs
bt0: targ 0 sync rate=10.00MB/s(100ns), offset=15
bt0: targ 4 async
bt0: targ 6 sync rate= 4.54MB/s(220ns), offset=15
bt0: Using Strict Round robin scheme
bt0 at 0x330 irq 11 on isa
bt0 waiting for scsi devices to settle
(bt0:0:0): "IBM DALS-3540 S60E" type 0 fixed SCSI 2
sd0(bt0:0:0): Direct-Access 516MB (1056768 512 byte sectors)
(bt0:4:0): "ARCHIVE VIPER 150 21247 B07:" type 1 removable SCSI 1
st0(bt0:4:0): Sequential-Access st0: Archive Viper 150 is a known rogue
density code 0x10, drive empty
(bt0:6:0): "TOSHIBA CD-ROM XM-3501TA 3054" type 5 removable SCSI 2
cd0(bt0:6:0): CD-ROM cd present.[324186 x 2048 byte records]
npx0 on motherboard
npx0: INT 16 interface
--
M. L. Dodson bdodson@scms.utmb.edu
409-772-2178 FAX: 409-772-1790
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