Hi All,
When benchmarking with ttcp/iperf I find that I get very different results when sending and receiving between two directly connected devices, depending on who the sender is.
When sending from one device I get:
But when sending from the other I get:
Both devices are using Intel gigabit NICs. Hardware-wise neither of these systems should be exhausted by performing this benchmark. Both are sending from RAM, not disk, and neither CPU is overloaded. During the benchmark the network path does not change is not otherwise saturated.
In this case one device is running FreeBSD 7.2-RELEASE, the other is OS X 10.5. In the above example the slower transfer came from the FreeBSD box.
What would cause a 40% difference in throughput?
When benchmarking with ttcp/iperf I find that I get very different results when sending and receiving between two directly connected devices, depending on who the sender is.
When sending from one device I get:
Code:
ttcp-t: buflen=8192, nbuf=2048, align=16384/0, port=5001 tcp -> 192.168.1.2
ttcp-t: socket
ttcp-t: connect
ttcp-t: 16777216 bytes in 0.19 real seconds = [B]84668.77 KB/sec[/B] +++
ttcp-t: 2048 I/O calls, msec/call = 0.10, calls/sec = 10583.60
ttcp-t: 0.0user 0.0sys 0:00real 47% 0i+0d 0maxrss 0+0pf 1340+0csw
But when sending from the other I get:
Code:
ttcp-t: buflen=8192, nbuf=2048, align=16384/0, port=5001 tcp -> 192.168.1.1
ttcp-t: socket
ttcp-t: connect
ttcp-t: 16777216 bytes in 0.32 real seconds = [B]51132.25 KB/sec[/B] +++
ttcp-t: 2048 I/O calls, msec/call = 0.16, calls/sec = 6391.53
ttcp-t: 0.0user 0.1sys 0:00real 33% 27i+1936d 1208maxrss 0+2pf 3173+7csw
Both devices are using Intel gigabit NICs. Hardware-wise neither of these systems should be exhausted by performing this benchmark. Both are sending from RAM, not disk, and neither CPU is overloaded. During the benchmark the network path does not change is not otherwise saturated.
In this case one device is running FreeBSD 7.2-RELEASE, the other is OS X 10.5. In the above example the slower transfer came from the FreeBSD box.
What would cause a 40% difference in throughput?