Date: Mon, 19 Aug 2002 18:36:34 -0700 (PDT) From: Carlos Carnero <zopewiz@yahoo.com> To: Luigi Rizzo <rizzo@icir.org> Cc: freebsd-net@FreeBSD.ORG Subject: Re: Bandwidth throttling with dummynet(4) Message-ID: <20020820013634.3113.qmail@web21410.mail.yahoo.com> In-Reply-To: <20020819154141.A41050@iguana.icir.org>
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Hello, > dummynet pipes use timers heavily, and i suspect > that the timer granularity in vmware might not be > as good as you would want yes, you're right. I changed some thing though: increased HZ in the kernel config from 1000 to 1500; and currently I'm running the virtual machine at a higher priority. Luckily I have a very fast host with lots of RAM. I did the timing (delay) checks and yes, it improved to a point that "almost" is where I want it to be (less than 5% dev :) > Also, 5Kbytes/s is a very low bandwidth, which > coupled with 50 queue slots (~75Kbytes with large > packets) will result in very large RTTs which could > in turn trigger useless retransmissions and > timeouts. I'll play more with the slots, but those speeds (~ 5KByte/s) are the ones that the real thing will use. I'm building a router for a friend that has to share a 256KBit/s link among 100 people :o I know that VMware is not exactly the best thing to test dummynet, but right now I have no other choice. It's an experience anyway. > cheers > luigi Thanks a lot, Carlos. > On Mon, Aug 19, 2002 at 01:33:23PM -0700, Carlos > Carnero wrote: > > Hi, > > > > I have a "lab" here where I'm testing (and > learning) > > traffic shaping with dummynet(4). I have a Windows > XP > > host computer and a couple of VMware virtual > > computers: one running FreeBSD 4.5-RELEASE-p18, > with > > two virtual Ethernet adapters and other running > NetBSD > > 1.5.2 with one adapter. My FreeBSD "box" is the > > router/gateway for the NetBSD box, providing > > firewalling and NAT. Pretty much a standard setup, > and > > it works OK (you should see the double NATting ;) > > > > Anyway, I have compiled into the kernel both IP > Filter > > and FreeBSD's own ipfw, with the purpose of > traffic > > shaping/bandwidth throttling. But the numbers I > get > > are not what I expect. For instance, my ipfw rules > are > > like: > > > > pipe 1000 config bw 5KByte/s queue 50 > > pipe 1001 config bw 5KByte/s queue 50 > > > > add 50000 pipe 1000 tcp from 192.168.250.3/32 to > any > > add 50001 pipe 1001 tcp from any to > 192.168.250.3/32 > > > > (192.168.250.3 being the NetBSD "box") But when I > > transfer a file using FTP from the Windows host I > get > > _almost_ 1 KByte. Note that I remove the pipes > speeds > > reach ~800-900 KByte/s, almost saturating the > > "virtual" Ethernet interfaces. Changing the pipe > > bandwidth to, say 25KByte/s in both pipes yield an > FTP > > speed of ~5-6 KByte/s. Is this OK or FTP is that > > inefficient? What other tests can I run to check > the > > bandwidth _not_ using FTP? > > > > IP Filter's ruleset is currently set to pass > > everything as quickly as it can :) > > > > Thanks a lot, > > Carlos. > > > > PS. Posting from Yahoo! until I solve some reverse > DNS > > bugs I inherited :| > > > > __________________________________________________ > > Do You Yahoo!? > > HotJobs - Search Thousands of New Jobs > > http://www.hotjobs.com > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > > with "unsubscribe freebsd-net" in the body of the message __________________________________________________ Do You Yahoo!? HotJobs - Search Thousands of New Jobs http://www.hotjobs.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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