From 79da1e411ba5f7ed0f667b470d075ad83e7fc593 Mon Sep 17 00:00:00 2001 From: Kevin Traynor Date: Fri, 25 Aug 2017 00:51:18 -0700 Subject: [PATCH] dpif-netdev: Change pmd selection order. Up to his point rxqs are sorted by processing cycles they consumed and assigned to pmds in a round robin manner. Ian pointed out that on wrap around the most loaded pmd will be the next one to be assigned an additional rxq and that it would be better to reverse the pmd order when wraparound occurs. In other words, change from assigning by rr to assigning in a forward and reverse cycle through pmds. Also, now that the algorithm has finalized, document an example. Suggested-by: Ian Stokes Signed-off-by: Kevin Traynor Signed-off-by: Darrell Ball --- Documentation/howto/dpdk.rst | 16 ++++++++++++++++ lib/dpif-netdev.c | 27 ++++++++++++++++++++++++++- tests/pmd.at | 2 +- 3 files changed, 43 insertions(+), 2 deletions(-) diff --git a/Documentation/howto/dpdk.rst b/Documentation/howto/dpdk.rst index a67f3a1fa..bac51de8e 100644 --- a/Documentation/howto/dpdk.rst +++ b/Documentation/howto/dpdk.rst @@ -123,6 +123,22 @@ automatically. The processing cycles that have been stored for each rxq will be used where known to assign rxqs to pmd based on a round robin of the sorted rxqs. +For example, in the case where here there are 5 rxqs and 3 cores (e.g. 3,7,8) +available, and the measured usage of core cycles per rxq over the last +interval is seen to be: + +- Queue #0: 30% +- Queue #1: 80% +- Queue #3: 60% +- Queue #4: 70% +- Queue #5: 10% + +The rxqs will be assigned to cores 3,7,8 in the following order: + +Core 3: Q1 (80%) | +Core 7: Q4 (70%) | Q5 (10%) +core 8: Q3 (60%) | Q0 (30%) + Rxq to pmds assignment takes place whenever there are configuration changes. QoS diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c index 7331b0bdb..1b2dc9b3d 100644 --- a/lib/dpif-netdev.c +++ b/lib/dpif-netdev.c @@ -3287,6 +3287,7 @@ struct rr_numa { int n_pmds; int cur_index; + bool idx_inc; }; static struct rr_numa * @@ -3343,13 +3344,37 @@ rr_numa_list_populate(struct dp_netdev *dp, struct rr_numa_list *rr) numa->n_pmds++; numa->pmds = xrealloc(numa->pmds, numa->n_pmds * sizeof *numa->pmds); numa->pmds[numa->n_pmds - 1] = pmd; + /* At least one pmd so initialise curr_idx and idx_inc. */ + numa->cur_index = 0; + numa->idx_inc = true; } } +/* Returns the next pmd from the numa node in + * incrementing or decrementing order. */ static struct dp_netdev_pmd_thread * rr_numa_get_pmd(struct rr_numa *numa) { - return numa->pmds[numa->cur_index++ % numa->n_pmds]; + int numa_idx = numa->cur_index; + + if (numa->idx_inc == true) { + /* Incrementing through list of pmds. */ + if (numa->cur_index == numa->n_pmds-1) { + /* Reached the last pmd. */ + numa->idx_inc = false; + } else { + numa->cur_index++; + } + } else { + /* Decrementing through list of pmds. */ + if (numa->cur_index == 0) { + /* Reached the first pmd. */ + numa->idx_inc = true; + } else { + numa->cur_index--; + } + } + return numa->pmds[numa_idx]; } static void diff --git a/tests/pmd.at b/tests/pmd.at index b6732eac5..e39a23a43 100644 --- a/tests/pmd.at +++ b/tests/pmd.at @@ -53,7 +53,7 @@ m4_define([CHECK_PMD_THREADS_CREATED], [ ]) m4_define([SED_NUMA_CORE_PATTERN], ["s/\(numa_id \)[[0-9]]*\( core_id \)[[0-9]]*:/\1\2:/"]) -m4_define([SED_NUMA_CORE_QUEUE_PATTERN], ["s/\(numa_id \)[[0-9]]*\( core_id \)[[0-9]]*:/\1\2:/;s/\(queue-id: \)0 2 4 6/\1/;s/\(queue-id: \)1 3 5 7/\1/"]) +m4_define([SED_NUMA_CORE_QUEUE_PATTERN], ["s/\(numa_id \)[[0-9]]*\( core_id \)[[0-9]]*:/\1\2:/;s/\(queue-id: \)1 2 5 6/\1/;s/\(queue-id: \)0 3 4 7/\1/"]) m4_define([DUMMY_NUMA], [--dummy-numa="0,0,0,0"]) AT_SETUP([PMD - creating a thread/add-port])