From owner-freebsd-hackers Tue Apr 30 03:49:34 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id DAA27274 for hackers-outgoing; Tue, 30 Apr 1996 03:49:34 -0700 (PDT) Received: from paloalto.access.hp.com (daemon@paloalto.access.hp.com [15.254.56.2]) by freefall.freebsd.org (8.7.3/8.7.3) with ESMTP id DAA27267 Tue, 30 Apr 1996 03:49:32 -0700 (PDT) Received: from fakir.india.hp.com by paloalto.access.hp.com with ESMTP (1.37.109.16/15.5+ECS 3.3) id AA111441356; Tue, 30 Apr 1996 03:49:22 -0700 Received: from localhost by fakir.india.hp.com with SMTP (1.37.109.16/15.5+ECS 3.3) id AA141971583; Tue, 30 Apr 1996 16:23:04 +0530 Message-Id: <199604301053.AA141971583@fakir.india.hp.com> To: hackers@freebsd.org, current@freebsd.org Subject: lmbench IDE anomaly Date: Tue, 30 Apr 1996 16:23:03 +0530 From: A JOSEPH KOSHY Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk 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 real memory = 16777216 (16384K bytes) avail memory = 14733312 (14388K bytes) Probing for devices on PCI bus 0: chip0 rev 1 on pci0:0 chip1 rev 1 on pci0:1 vga0 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): 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 ----