On Fri, 2016-04-15 at 15:33 -0700, Eric Dumazet wrote: > On Fri, 2016-04-15 at 21:02 +0000, Butler, Peter wrote: > > (Please keep me CC'd to all comments/responses) > > > > I've tried a kernel upgrade from 3.4.2 to 4.4.0 and see a marked drop in > > networking performance. Nothing was changed on the test systems, other > > than the kernel itself (and kernel modules). The identical .config used to > > build the 3.4.2 kernel was brought over into the 4.4.0 kernel source tree, > > and any configuration differences (e.g. new parameters, etc.) were taken as > > default values. > > > > The testing was performed on the same actual hardware for both kernel > > versions (i.e. take the existing 3.4.2 physical setup, simply boot into the > > (new) kernel and run the same test). The netperf utility was used for > > benchmarking and the testing was always performed on idle systems. > > > > TCP testing yielded the following results, where the 4.4.0 kernel only got > > about 1/2 of the throughput: > > > > Recv Send Send Utilization > > Service Demand > > Socket Socket Message Elapsed Send Recv > > Send Recv > > Size Size Size Time Throughput local remote > > local remote > > bytes bytes bytes secs. 10^6bits/s % S % S > > us/KB us/KB > > > > 3.4.2 13631488 13631488 8952 30.01 9370.29 10.14 6.50 > > 0.709 0.454 > > 4.4.0 13631488 13631488 8952 30.02 5314.03 9.14 14.31 > > 1.127 1.765 > > > > SCTP testing yielded the following results, where the 4.4.0 kernel only got > > about 1/3 of the throughput: > > > > Recv Send Send Utilization > > Service Demand > > Socket Socket Message Elapsed Send Recv > > Send Recv > > Size Size Size Time Throughput local remote > > local remote > > bytes bytes bytes secs. 10^6bits/s % S % S > > us/KB us/KB > > > > 3.4.2 13631488 13631488 8952 30.00 2306.22 13.87 13.19 > > 3.941 3.747 > > 4.4.0 13631488 13631488 8952 30.01 882.74 16.86 19.14 > > 12.516 14.210 > > > > The same tests were performed a multitude of time, and are always > > consistent (within a few percent). I've also tried playing with various > > run-time kernel parameters (/proc/sys/kernel/net/...) on the 4.4.0 kernel > > to alleviate the issue but have had no success at all. > > > > I'm at a loss as to what could possibly account for such a discrepancy... > > Maybe new kernel is faster and you have drops somewhere ? > > nstat >/dev/null > netperf -H ... > nstat > > Would help >
Are you receiving my mails, or simply ignoring them ? Thanks.
