Hi,

When I was testing a new NIC, I found the single stream scp performance was 
almost 8 time slower than Linux on the RX side. Initially I thought it might be 
something with the NIC. But when I switched to sending the file on localhost, 
the numbers stay the same. 

Here I was sending a 2GB file from sender to receiver using scp.  FreeBSD is a 
recent NON-DEBUG build from CURRENT. The Ubuntu Linux kernel is 6.2.0. Both run 
in HyperV VMs on the same type of hardware. The FreeBSD VM has 16 vcpus, while 
Ubuntu VM has 4 vcpu.

Sender          Receiver        throughput
Linux           FreeBSD         70 MB/s
Linux           Linux           550 MB/s
FreeBSD FreeBSD 70 MB/s
FreeBSD Linux           350 MB/s
FreeBSD         localhost       70 MB/s
Linux           localhost       550 MB/s

>From theses test, it seems I can rule out the issue on NIC and its driver. 
>Looks the FreeBSD kernel network stack is much slower than Linux on single 
>stream TCP, or there are some problem with scp?

I also tried turning on following kernel parameters on FreeBSD kernel. But it 
makes no difference, neither do the other tcp cc algorithms such as htcp and 
newreno.

net.inet.tcp.soreceive_stream="1"
net.isr.maxthreads="-1"
net.isr.bindthreads="1"

net.inet.ip.intr_queue_maxlen=2048
net.inet.tcp.recvbuf_max=16777216
net.inet.tcp.recvspace=419430
net.inet.tcp.sendbuf_max=16777216
net.inet.tcp.sendspace=209715
kern.ipc.maxsockbuf=16777216

Any ideas?

Thanks,
Wei

Reply via email to