> On 29. Jun 2023, at 11:51, Murali Krishnamurthy <[email protected]> wrote: > > Hello FreeBSD Transport experts, > We are evaluating performance of FreeBSD 13 VM on ESX hypervisor in long RTT > setup and happened to compare the performance with Linux VM with same > hypervisor. > We see a substantially better performance with Linux getting close to the BDP > limit, whereas BSD 13 not filling up the pipe enough. > We are trying to figure out what could lead to such a huge difference and > feel we could be missing something here. > Could you please help us to know if there is a way to make it perform better? > Setup details: > We have 2 ESX hypervisors where 2 VMs (one FreeBSD 13 and one Ubuntu > 23.04/Linux kernel 6.2) were launched on each hypervisor. > Then we ran iperf between, > • BSD 13 <-> BSD 13 > • Ubuntu <-> Ubuntu > Even though the network environment were same in both cases, we see Ubuntu > performing much better. > Below are connection parameters: > Socket buffer: 16MB > TCP CC Algo: Cubic. We used this as this is suitable for Long Fat Networks. > Ping RTT: 100 ms between the two end points. > We kept all other parameters to default on both Linux and BSD. > BDP for 16MB Socket buffer: 16 MB * (1000 ms * 100ms latency) * 8 bits/ 1024 > = 1.25 Gbps > Ubuntu consistently hits around 1 Gbps Bitrate almost reaching the BDP limit. > FreeBSD 13 shows a Bit rate between the range of 300-600 Mbps only. So it > seems to be doing half as good as Linux. > For lower socket buffer of 4MB, both FreeBSD and Linux seem to do same and > able to meet BDP of 300 Mbps consistently. > Larger socket buffer seems to have an issue. > Please let us know if there are ways to fine tune the system parameters to > make BSD perform better. > Or any other suggestions/queries welcome. > Regards > Murali Hi Murali,
I'll bring this up on the biweekly transport call. Best regards Michael
