On Sun, 2015-08-30 at 11:29 +0530, Raghavendra K T wrote: > Docker container creation linearly increased from around 1.6 sec to 7.5 sec > (at 1000 containers) and perf data showed 50% ovehead in snmp_fold_field. > > reason: currently __snmp6_fill_stats64 calls snmp_fold_field that walks > through per cpu data of an item (iteratively for around 36 items). > > idea: This patch tries to aggregate the statistics by going through > all the items of each cpu sequentially which is reducing cache > misses. > > Docker creation got faster by more than 2x after the patch. > > Result: > Before After > Docker creation time 6.836s 3.25s > cache miss 2.7% 1.41% > > perf before: > 50.73% docker [kernel.kallsyms] [k] snmp_fold_field > 9.07% swapper [kernel.kallsyms] [k] snooze_loop > 3.49% docker [kernel.kallsyms] [k] veth_stats_one > 2.85% swapper [kernel.kallsyms] [k] _raw_spin_lock > > perf after: > 10.57% docker docker [.] scanblock > 8.37% swapper [kernel.kallsyms] [k] snooze_loop > 6.91% docker [kernel.kallsyms] [k] snmp_get_cpu_field > 6.67% docker [kernel.kallsyms] [k] veth_stats_one > > changes/ideas suggested: > Using buffer in stack (Eric), Usage of memset (David), Using memcpy in > place of unaligned_put (Joe). > > Signed-off-by: Raghavendra K T <raghavendra...@linux.vnet.ibm.com> > ---
Acked-by: Eric Dumazet <eduma...@google.com> Thanks. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
