On Wednesday 28 April 2004 00:21, Stephen Hemminger wrote:
quoted
This takes the suggestion and makes all the locked skb_ stuff, not inline.
It showed a 3% performance improvement when doing single TCP stream over 1G
Ethernet between SMP machines. Test was average of 10 iterations of
iperf for 30 seconds and SUT was 4 way Xeon. Http performance difference
was not noticeable (less than the std. deviation of the test runs).
The original tests were suspect for a whole lot of reasons. Running the proper
tests shows no performance differences. The best theory as to why there was
a difference in earlier tests is that memory debugging was enabled; that caused
each buffer to be overwritten with a memset. When that happened, the test
ends up measuring the speed of the memory and cache bandwidth, not the CPU or
the network.