Take this with a grain of salt, as I really haven't done enough testing to state anything conclusive.
However, under ESXi 5.1u3, I was only able to get my iperf scores up to 2/3Gb/s, with the occasional 5Gb/s bust on my 10Gb/s network.
With ESXi 5.5u2 (patches as of today's date) I am able to get scores like this fairly consistently:
Not bad, not bad.
Even if the scores are not accurate, it's at least showing a dramatic improvement over my 5.1 configuration.
This is from a FreeBSD 10.1 VM under ESXi 5.5 to a bare-metal FreeBSD 10.1. VM-to-VM performance is a bit lower, but still quite good:
The FreeBSD VM's are still vmx-08, and I'm using the built-in vmx driver in FreeBSD 10.1
This is also with the default configuration for sysctl values - I was planning on building a small script to check different tcp settings, but with speed like this, there are more pressing things to worry about.
However, under ESXi 5.1u3, I was only able to get my iperf scores up to 2/3Gb/s, with the occasional 5Gb/s bust on my 10Gb/s network.
With ESXi 5.5u2 (patches as of today's date) I am able to get scores like this fairly consistently:
[ 3] 0.0- 5.0 sec 5.70 GBytes 9.79
Gbits/sec
[ 3] 5.0-10.0 sec 5.69 GBytes 9.77
Gbits/sec
[ 3] 10.0-15.0 sec 5.69 GBytes 9.77
Gbits/sec
[ 3] 15.0-20.0 sec 5.70 GBytes 9.80
Gbits/sec
[ 3] 0.0-20.0 sec 22.8 GBytes 9.78
Gbits/sec
Not bad, not bad.
Even if the scores are not accurate, it's at least showing a dramatic improvement over my 5.1 configuration.
This is from a FreeBSD 10.1 VM under ESXi 5.5 to a bare-metal FreeBSD 10.1. VM-to-VM performance is a bit lower, but still quite good:
[ ID] Interval
Transfer Bandwidth
[ 3] 0.0- 5.0 sec 4.89 GBytes 8.41
Gbits/sec
[ 3] 5.0-10.0 sec 5.46 GBytes 9.37
Gbits/sec
[ 3] 10.0-15.0 sec 4.32 GBytes 7.42
Gbits/sec
[ 3] 15.0-20.0 sec 4.87 GBytes 8.37
Gbits/sec
[ 3] 0.0-20.0 sec 19.5 GBytes 8.39
Gbits/sec
The FreeBSD VM's are still vmx-08, and I'm using the built-in vmx driver in FreeBSD 10.1
This is also with the default configuration for sysctl values - I was planning on building a small script to check different tcp settings, but with speed like this, there are more pressing things to worry about.