On Sun, 24 May 2015 12:02:32 +0300 Reco <recovery...@gmail.com> wrote:
> Hi. > > On Sun, 24 May 2015 10:36:39 +0200 > Petter Adsen <pet...@synth.no> wrote: > > > I've been trying to improve NFS performance at home, and in that > > process i ran iperf to get an overview of general network > > performance. I have two Jessie hosts connected to a dumb switch > > with Cat-5e. One host uses a Realtek RTL8169 PCI controller, and > > the other has an Intel 82583V on the motherboard. > > > > iperf maxes out at about 725Mbps. At first I thought maybe the > > switch could be at fault, it's a really cheap one, so I connected > > both hosts to my router instead. Didn't change anything, and it had > > no significant impact on the load on the router. I can't try to run > > iperf on the router (OpenWRT), though, as it maxes out the CPU. > > > > Should I be getting more than 725Mbps in the real world? > > A quick test in my current environment shows this: > > [ ID] Interval Transfer Bandwidth > [ 3] 0.0-10.0 sec 1.10 GBytes 941 Mbits/sec > > Two hosts, connected via Cisco 8-port unmanaged switch, Realtek 8168e > on one host, Atheros Attansic L1 on another. > > On the other hand, the same test, Realtek 8139e on one side, but with > lowly Marvell ARM SOC on the other side shows this: > > [ ID] Interval Transfer Bandwidth > [ 3] 0.0-10.0 sec 534 MBytes 448 Mbits/sec > > So - you can, definitely, and yes, it depends. That last one, would that be limited because of CPU power? > > Could there be a driver issue, or some settings that aren't optimal? > > Check your iptables rules if any. Especially nat and mangle tables. None. iptables are currently disabled on both sides. > Try the same test but use UDP instead of TCP. Only gives me 1.03Mbits/sec :) > Increase TCP window size (those net.core.rmem/wmem sysctls) on both > sides. It is currently 85KB and 85.3KB, what should I try setting them to? > Try increasing MTU above 1500 on both sides. Likewise, increase to what? > Use crossover cable if everything else fails. If I have one. I read somewhere that newer interfaces will auto-negotiate if you use a straight cable as a crossover, is that true? Also, the machine with the Realtek PCI adapter has a Marvell 88E8001 on the motherboard, but I haven't used it for years since there were once driver problems. Those are probably fixed now, I will try that once I can. Didn't think of it before. > > Unfortunately, > > these are the only two hosts I have with Gbit interfaces (except the > > router), so I can't test with another host. > > > > Could this be a MB/MiB issue? The iperf man page doesn't say which > > it reports. (Well, it says "Mbit/Mbyte", so I assume it does not > > mean MiB) > > No. (1024*1024*1024 - 1000*1000*1000)/1024/1024 = 70.32. > You can mistake by 70Mbps at most in this scenario, not by 300. I knew it wouldn't account for 275MB, but it could be a portion of it. Thanks for your response, though, I'm already learning things :) Petter -- "I'm ionized" "Are you sure?" "I'm positive."
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