Date: Sun, 19 Mar 2006 12:04:13 +0100 From: "OxY" <oxy@field.hu> To: "Jin Guojun \(VFFS\)" <g_jin@lbl.gov> Cc: freebsd-performance@freebsd.org Subject: Re: packet drop with intel gigabit / marwell gigabit Message-ID: <000601c64b44$db8dcb00$0201a8c0@oxy> References: <000a01c64a81$45eb6850$0201a8c0@oxy> <441BF838.1080600@mac.com><000601c64a87$51d7dee0$0201a8c0@oxy> <441BFF26.90807@mac.com> <000e01c64a8f$1b2bec80$0201a8c0@oxy> <441CAA8D.3020308@lbl.gov> <000401c64b33$7561d940$0201a8c0@oxy> <441D3698.10300@lbl.gov>
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----- Original Message ----- From: "Jin Guojun (VFFS)" <g_jin@lbl.gov> To: "OxY" <oxy@field.hu> Cc: "Chuck Swiger" <cswiger@mac.com>; <freebsd-performance@freebsd.org> Sent: Sunday, March 19, 2006 11:46 AM Subject: Re: packet drop with intel gigabit / marwell gigabit > OxY wrote: > >> CPU utilization is 0% if apache is not running and 10-20%, when running >> and >> serving 30-40 concurrent downloads (traffic is 3-4MB/s on fxp0 interface) > > Is the number 3-4MB/s for per stream or the total for all 30-40 streams? > Are these downloads sent to a disk? it's a total, 30-40 streams get the files from two sata disks in raid1 > >> i measured the network performance with 'iperf' util, started the server >> on my box >> and benchmarked with a client on the other gigabit machine. >> it showed 0% packet drop, when apache was not running and 4-7%, when >> running.. >> then i checked how it behave when i shut down apache and init a local >> file copy from one >> (not system!) disk to other (not system disk either). packet drop was >> 5-10%, due to the higher load. >> so i think interrupts or just the load takes the network performance, but >> i have no clue how to fix it. >> is it possible that the 2000+ xp amd is just weak to serve such a >> traffic? (em0 traffic's maximum is 18-23MB/s) >> i think it might be around 30MB/s without packet drop. > > First let's clear the notation -- Is 30MB/s (MBytes/s) = 240Mb/s (Mbit/s) > or MB/s means Mbits/s > If MB/s is MBytes/s and you also write this amount data to a disk, plus > other traffic on fxp0 to disk too, > then your problem may be bonded by memory bandwidth because CPU > utilization is low: > (240 + 24~32) x 2 is about 535 Mbit/s (some chipset/motherboard has low > memory BW for AMD) > If this is true, then this no thing you can tune. What does the chipset > (Motherboard) this machine have? 30MB/s is Megabytes/sec, currently i have 18-20MB/s peak and 15MB/s avg. it's not 535Mbit/s, because i only download it to my machine, no upload. disks are different from apache disks, these disks have own controller in one pci slot. the packet drop is 5-7% at 200Mbit iperf test, 100Mbit drop is around zero. i have <ASUS A7V8X> on motherboard which has VIA KT400 northbridge http://uk.asus.com/products4.aspx?modelmenu=2&model=226&l1=3&l2=13&l3=62 i have an ABIT BE7 (http://www.abit.com.tw/page/uk/motherboard/motherboard_detail.php?pMODEL_NAME=BE7&fMTYPE=Socket%20478&pPRODINFO=Specifications) resting somewhere, could it improve the network performance with a P4-2.4GHZ(533FSB)? (i don't want Intel-AMD flame :) ) dmesg if available here: http://field.hu/dmesg.txt system disks are ad4 and ad6 in raid 1, these have the files for apache users (first i thought system disks & apache are the problem, tested on other disk, have the same result)
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