svn commit: r280759 - head/sys/netinet

Gleb Smirnoff glebius at FreeBSD.org
Mon Mar 30 15:27:25 UTC 2015


On Mon, Mar 30, 2015 at 05:23:48PM +0200, Emeric POUPON wrote:
E> Hello,
E> 
E> Sorry for late response, I didn't notice this issue was discussed here.
E> 
E> In one of our tests, we have several (up to 12) cpu that emit packets with the same src, dst and protocol to a remote host.
E> We did this patch since we observed bad packet reassembly on the remote host, due to different fragments emitted with the same ip id.
E> It was an IPsec test (emitting ESP packets) but I guess we could easily reproduce this problem using several "ping -i 0 -s BIG_SIZE_HERE DST" commands running in parallel.
E> 
E> Even if we reached something like 1M pps, it is likely that we did not see any performance penalty since the IPsec stack is quite time consuming.
E> Now, the question is: is there a real performance issue here or is it likely to be hidden by other problems?
E> 
E> If it is a real problem, maybe an acceptable tradeoff would be to make the counter per CPU and:
E> - initialize it with the cpu id,
E> - increment it by the number of cpus.
E> 
E> What do you think?

I already posted a patch that makes the counter per CPU. Can you please test it?

-- 
Totus tuus, Glebius.


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