Date: Sun, 16 Jan 2005 23:40:57 +0100 From: Jochen Keil <J.Keil@gmx.de> To: freebsd-questions@freebsd.org Subject: different behaviour between 4.x and 5.x (ping response/disk io) Message-ID: <41EAED79.8080504@gmx.de>
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Hi all. I got a dual Piii 800 box here with these specifications: -Supermicro 370DL3 Mainboard -Adaptec aic7892 Ultra160 SCSI adapter (onboard) -2x 256MB Micron ECC RAM (tested with memtest) -2x IBM IC35L036UWDY10-0 (SCSI Drives, only one connected for testing) -LG GSA-4040B (connected via onboard IDE Controller) (a few IDE drives which weren't connected für testing) Full dmesg output is attached to the end of this email. Now to the description of my problem. I tested various Operating systems on this box, FreeBSD 5.3, NetBSD 2.0, FreeBSD 4.11 and an elder version of the Knoppix (Linux 2.4) CD. Every installation except FreeBSD 4.11 showed almost the same behaviour when doing the following test. First i ran iozone on the SCSI drive. While the benchmark was performed i issued a ping to another host in the network. The result drove me insane. Wether with the onboard fxp0 either the em0 i was able to get a "stable" ping response time which looks like that: i get a bunch (~20-30, depends on disk io) of ping response times around 0.2ms and then there are some really long response times above 1ms (the longest took about 90ms). However FreeBSD 4.x seems to be the only exception to this as it gives me over a complete iozone test only three pings with a response time around 1ms. The other ping times are mostly around 0.2ms with some seldom peaks at 0.5-0.6ms. Due to this behaviour i figured out that this cannot be the fault of the hardware, at least i hope so. A hint from a NetBSD Mailing List pointed me to have a look at the interrupts. On disk IO the interrupt rate on ahc0 is going up to around 300/s. But this is all the same for FreeBSD 4.x and 5.x (i used vmstat -i for that). There also seems to be no difference between using SMP and a single CPU kernel (Information based on FreeBSD 5.3 and NetBSD 2.0 tests as i didn't test this with FreeBSD 4.11 yet). Now i am really puzzled because i cannot understand why 4.x behaves relatively good compared to 5.x on this specific issue. Is there a good explanation or does one have to investigate this further? The NetBSD Mailing List i'm talking about can be found here: http://mail-index.netbsd.org/netbsd-users/2005/01/. (Discussion starts on 05.01.2005: High Load / bad response times). I'm looking forward to your answers and with kind regards, Jochen Keil Dmesg from 4.11: FreeBSD 4.11-RC2 #0: Sun Jan 2 09:47:04 GMT 2005 root@perseus.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC Timecounter "i8254" frequency 1193182 Hz CPU: Intel Pentium III (799.62-MHz 686-class CPU) Origin = "GenuineIntel" Id = 0x683 Stepping = 3 Features=0x383fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,MMX,FXSR,SSE> real memory = 536805376 (524224K bytes) config> di pcic0 config> di psm0 config> di sio1 config> di sio0 config> di ppc0 config> di fdc0 config> di bt0 config> di ata1 config> di aic0 config> di aha0 config> di adv0 config> q avail memory = 516833280 (504720K bytes) Preloaded elf kernel "kernel" at 0xc0556000. Preloaded userconfig_script "/boot/kernel.conf" at 0xc055609c. Pentium Pro MTRR support enabled md0: Malloc disk Using $PIR table, 9 entries at 0xc00f5230 npx0: <math processor> on motherboard npx0: INT 16 interface pcib0: <ServerWorks NB6635 3.0LE host to PCI bridge> on motherboard pci0: <PCI bus> on pcib0 pci0: <S3 968 graphics accelerator> at 3.0 irq 11 fxp0: <Intel 82559 Pro/100 Ethernet> port 0xd800-0xd83f mem 0xfe800000-0xfe8fffff,0xfe9ef000-0xfe9effff irq 9 at device 6.0 on pci0 fxp0: Ethernet address 00:30:48:21:74:63 inphy0: <i82555 10/100 media interface> on miibus0 inphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto isab0: <ServerWorks IB6566 PCI to ISA bridge> at device 15.0 on pci0 isa0: <ISA bus> on isab0 atapci0: <ServerWorks ROSB4 ATA33 controller> port 0xffa0-0xffaf at device 15.1 on pci0 ata0: at 0x1f0 irq 14 on atapci0 ata1: at 0x170 irq 15 on atapci0 ohci0: <OHCI (generic) USB controller> mem 0xfeaff000-0xfeafffff irq 10 at device 15.2 on pci0 usb0: OHCI version 1.0, legacy support usb0: <OHCI (generic) USB controller> on ohci0 usb0: USB revision 1.0 uhub0: (0x1166) OHCI root hub, class 9/0, rev 1.00/1.00, addr 1 uhub0: 4 ports with 4 removable, self powered pcib1: <ServerWorks NB6635 3.0LE host to PCI bridge> on motherboard pci1: <PCI bus> on pcib1 ahc0: <Adaptec aic7892 Ultra160 SCSI adapter> port 0xe800-0xe8ff mem 0xfebff000-0xfebfffff irq 11 at device 3.0 on pci1 aic7892: Ultra160 Wide Channel A, SCSI Id=7, 32/253 SCBs orm0: <Option ROM> at iomem 0xc0000-0xc7fff on isa0 pmtimer0 on isa0 atkbdc0: <Keyboard controller (i8042)> at port 0x60,0x64 on isa0 atkbd0: <AT Keyboard> flags 0x1 irq 1 on atkbdc0 kbd0 at atkbd0 vga0: <Generic ISA VGA> at port 0x3c0-0x3df iomem 0xa0000-0xbffff on isa0 sc0: <System console> at flags 0x100 on isa0 sc0: VGA <16 virtual consoles, flags=0x300> acd0: DVD-R <HL-DT-ST DVDRAM GSA-4040B> at ata0-master PIO4 Waiting 15 seconds for SCSI devices to settle Mounting root from ufs:/dev/da0s1a da0 at ahc0 bus 0 target 1 lun 0 da0: <IBM IC35L036UWDY10-0 S28C> Fixed Direct Access SCSI-3 device da0: 160.000MB/s transfers (80.000MHz, offset 127, 16bit), Tagged Queueing Enabled da0: 34715MB (71096640 512 byte sectors: 255H 63S/T 4425C)
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