Keith, My understanding is that iperf runs parallel threads when launched with the -P # option. I'm using this one:
# ./iperf -v iperf version 2.0.5 (08 Jul 2010) pthreads The test results I posted earlier showed that the total throughput reported by iperf is slightly lower when running 10 threads in parallel between the two servers (-P 10, SUM = 2.51 Gbit/s) than when running a single thread (2.93 Gbit/s). On the sender side, while running the tests, with a single thread one CPU core goes to about 85% utilization with two others around 15-25% (usr). With 3 or more threads, one core is pegged at 100% and a few others reach around 10-40%. Furthermore, to test your hypothesis I tried running the iperf server and client on the same machine (the one with Dual Xeon E5-2620). Total throughput reaches a maximum of about 200 Gbit/s at 6 threads, remaining fairly constant when the number of threads is increased further. At 6 threads, load is spread fairly evenly at 30-70 % on each of 24 cores. At 100 threads, total throughput is still about 170 Gbit/s, with all cores maxed out at 97+. To me, this looks like the single-threaded bottleneck is somewhere further down the stack. What do you think? Thanks, Chris Am 21.07.2014 um 15:51 schrieb Keith Wesolowski via smartos-discuss <[email protected]>: > On Mon, Jul 21, 2014 at 01:31:05PM +0200, Chris Ferebee via smartos-discuss > wrote: > >> Observing CPU utilization during the test using mpstat, I see that all cores >> but one are mostly idle, and one core goes to 100% utilization, even when >> running iperf with a single thread. >> >> Nick suggested that based on this, I should try increasing rx_queue_number >> and tx_queue_number for the ixgbe driver. AFAICS, I would need to do that in >> /kernel/drv/ixgbe.conf, which in turn means I need to do something like > > A more likely hypothesis to test would be that the single-threaded > generation of data to be placed on the network is your limiting factor. > > > ------------------------------------------- > smartos-discuss > Archives: https://www.listbox.com/member/archive/184463/=now > RSS Feed: https://www.listbox.com/member/archive/rss/184463/24804823-eebbfb1e > Modify Your Subscription: https://www.listbox.com/member/?&; > Powered by Listbox: http://www.listbox.com ------------------------------------------- smartos-discuss Archives: https://www.listbox.com/member/archive/184463/=now RSS Feed: https://www.listbox.com/member/archive/rss/184463/25769125-55cfbc00 Modify Your Subscription: https://www.listbox.com/member/?member_id=25769125&id_secret=25769125-7688e9fb Powered by Listbox: http://www.listbox.com
