Messages in this thread | | | Subject | RE: TCP stream performance regression due to c377411f2494a931ff7facdbb3a6839b1266bcf6 | From | Eric Dumazet <> | Date | Thu, 24 Jun 2010 19:18:54 +0200 |
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Le vendredi 18 juin 2010 à 16:26 +0800, Zhang, Yanmin a écrit : > More info about the testing: > It's a loopback testing. We start one client netperf process to communicate with netserver process in a stream TCP testing. To reduce the cpu cache effect, we bind the 2 processes on 2 different physical cpus. > #taskset -c 0 ./netserver > #taskset -c 15 ./netperf -t TCP_STREAM -l 60 -H 127.0.0.1 -i 50,3 -I 99,5 -- -s 57344 -S 57344 -m 4096 >
Thanks guys
We corrected a proven vulnerability in network stack.
If you want better netperf results, just increase size of your sockets buffers. 57344 is _very_ low for localhost communication, given lo MTU is 16436.
As we also increased skb->truesize lately, you might also increase buffer size regardless of this (net: sk_add_backlog() take rmem_alloc into account) commit.
In my case, I saw following improvement :
Under huge stress from a multiqueue/RPS enabled NIC, a single flow udp receiver can now process ~200.000 pps (instead of ~100 pps before the patch) on a 8 core machine.
Thats a 200.000 % increase, in a situation no tuning was possible ;)
> >>-----Original Message----- > >>From: Shi, Alex > >>Sent: 2010年6月18日 15:17 > >>To: eric.dumazet@gmail.com; davem@davemloft.net > >>Cc: Chen, Tim C; Zhang, Yanmin; linux-kernel@vger.kernel.org > >>Subject: TCP stream performance regression due to > >>c377411f2494a931ff7facdbb3a6839b1266bcf6 > >> > >>In our netperf testing, TCP_STREAM56 shows about 20% or more performance > >>regression on WSM/NHM and tigerton machines. The testing boot up both > >>netserver and client on localhost. The testing command like this: > >>./snapshot_script_net TC_STREAM56 127.0.0.1 > >> > >>We found the following commit causes this issue. > >>c377411f2494a931ff7facdbb3a6839b1266bcf6 > >>Revert this commit will recover this regression on all machine. > >> > >>Regards! > >>Alex >
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