[netperf-talk] netperf2.4.4 on linux, socket size issue ?

[Andrew Gallatin]

Rick Jones writes:
 > beginning and the end of the run.  When one accepts the defaults, it 
 > will allow one to see how large the Linux autotuning let things get.  If 
 > you then use _that_ value in a -S/-s option I suspect you will achieve 
 > the same results as accepting the defaults - assuming that the values of 
 > (iirc) net.core.rmem_max and .wmem_max allow it.
 > 

There will be a difference in that the cache impact of the message
size will be different.  If you take the defaults, I beleive netperf
will default the message size to the socket buffer size.  So you'd
want to use netperf -- -m ORIG_SIZE -s NEW_SIZE to keep the same
message size.

If, for example, you use the defaults and see that a 64K socket
buffer size was seen at the start, and a 4MB size was seen at
the end, you might want to do netperf ... -- -m 64KB -s 4MB.

Drew