This series introduces a new mechanism (ovsthread-stats) to count statistics for different objects (mostly flows) in OVS. Each thread has its own copy of the counters, so updates are very cheap.
The commits are organized in this order: - Group statistics update in dpif-netdev (unrelated to the rest of the series) - New RCU mechanisms (compare and exchange) and data structures (rcu singly linked list) - New thread-stats module - Changes to dpif-netdev and ofproto to use the new module - Remove old ovsthread_stats No mutex is used during statistics update, therefore we have slightly better single thread performance and greater scalability The current limitations are: - For each flow (or object that needs to keep stats) exactly one cacheline is allocated. This is ok for now, because most of the users need a little less that a cacheline. - The memory is recycled but never freed. - ovsthread_stats_clear() clears one bucket at a time. A concurrent reader might see an inconsistent view. This limitation was also present in the old ovsthread_stats mechanism, used in the datapath. Right now this is not a problem because we never have one thread that is clearing while another thread is reading stats. Jarno helped me a lot with the RCU mechanisms and data structures Daniele Di Proietto (10): dpif-netdev: Group statistics updates in the slow path ovs-rcu: Introduce ovsrcu_compare_exchange() ovs-rcu: Allow static pointer non-NULL initialization rcu-slist: Introduce RCU-protected singly linked list ovs-thread-stats: New truly per-thread stats module ovs-thread-stats: Added simple testcase dpif-netdev: Use new ovs-thread-stats for flow statistics ofproto-dpif: Use new ovs-thread-stats for rule_dpif stats dpif-netdev: Use new ovs-thread-stats for datapath stats ovs-thread: Removed old unused ovsthread_stats lib/automake.mk | 3 + lib/dpif-netdev.c | 176 +++++++++---------- lib/ovs-rcu.h | 87 +++++++++- lib/ovs-thread-stats.c | 393 +++++++++++++++++++++++++++++++++++++++++++ lib/ovs-thread-stats.h | 236 ++++++++++++++++++++++++++ lib/ovs-thread.c | 56 +----- lib/ovs-thread.h | 32 ---- lib/rcu-slist.h | 84 +++++++++ ofproto/ofproto-dpif-xlate.c | 2 +- ofproto/ofproto-dpif.c | 103 +++++++++--- tests/automake.mk | 2 + tests/test-stats.c | 162 ++++++++++++++++++ tests/testsuite.at | 1 + tests/threadstats.at | 4 + 14 files changed, 1129 insertions(+), 212 deletions(-) create mode 100644 lib/ovs-thread-stats.c create mode 100644 lib/ovs-thread-stats.h create mode 100644 lib/rcu-slist.h create mode 100644 tests/test-stats.c create mode 100644 tests/threadstats.at -- 2.1.0.rc1 _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
