other tests with dragonfly

Sepherosa Ziehau sepherosa at gmail.com
Sun May 4 00:41:45 PDT 2014

On Sun, May 4, 2014 at 3:26 PM, Wojciech Puchar
<wojtek at wojtek.tensor.gdynia.pl> wrote:
>> For what it's worth, Sepherosa Ziehau has been putting a lot of work into
>> reducing CPU use on high-bandwidth connections:
>> http://lists.dragonflybsd.org/pipermail/users/2014-March/128240.html
> if i understand correctly it would reduce CPU usage greatly on highly loaded
> server doing lots of TCP transfers.

There is another commit to reduce port token contention.  Recent TCP
connect(2)+kqueue(2) using 8 processes could do ~300Kconns/s; compared
w/ ~275Kconns/s before the port token splitting work.  The TCP
connect(2)+kqueue(2) is cpu bound on Dfly now (~0% idle time on all
HTs).  Admittedly, I still can't max out 1000M network w/ connect(2)
on my testing hardware (the theoretical TCP connect rate for 1000M
network should be ~335Kconns/s).

However, on the other hand, the TCP accept(2)+kqueue(2) is quite good
w/ SO_REUSEPORT, sink @~335Kconns/s w/ pretty much idle time on each

Best Regards,

> looks like core i7 with 4 cores and 8 threads can saturate completely 2
> 10Gbit/s ethernet interfaces with both directions.
> better than FreeBSD, but anyway - it's still over 3 CPU cycles per byte
> transmitted. still very high CPU usage
>> http://lists.dragonflybsd.org/pipermail/commits/2014-March/269653.html
>> On Sat, May 3, 2014 at 6:54 AM, Wojciech Puchar
>> <wojtek at wojtek.tensor.gdynia.pl> wrote:
>>       as my friend advised me, i did flood test - generated lots of random
>> UDP packets with size between 52 and 100 bytes.
>>       Actually low end ethernet card in my laptop was a limit (rl), but
>> compared FreeBSD 10 with custom kernel and dragonfly 3.6 with generic kernel
>> (that have diagnostics check
>>       compiled by default).
>>       dragonfly used about 3 times less CPU.
>>       no tests on gigabit or 10 gigabit ethernet and multicore machine for
>> now.
>>       quite good.
>>       CPU load on more normal cases (like transfering files using rcp) is
>> lower too, but difference is smaller like 1.5-2 times.

Tomorrow Will Never Die

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