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-rw-r--r--lib/dim/rdma_dim.c109
1 files changed, 109 insertions, 0 deletions
diff --git a/lib/dim/rdma_dim.c b/lib/dim/rdma_dim.c
new file mode 100644
index 0000000000..88f7794867
--- /dev/null
+++ b/lib/dim/rdma_dim.c
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/*
+ * Copyright (c) 2019, Mellanox Technologies inc. All rights reserved.
+ */
+
+#include <linux/dim.h>
+
+static int rdma_dim_step(struct dim *dim)
+{
+ if (dim->tune_state == DIM_GOING_RIGHT) {
+ if (dim->profile_ix == (RDMA_DIM_PARAMS_NUM_PROFILES - 1))
+ return DIM_ON_EDGE;
+ dim->profile_ix++;
+ dim->steps_right++;
+ }
+ if (dim->tune_state == DIM_GOING_LEFT) {
+ if (dim->profile_ix == 0)
+ return DIM_ON_EDGE;
+ dim->profile_ix--;
+ dim->steps_left++;
+ }
+
+ return DIM_STEPPED;
+}
+
+static int rdma_dim_stats_compare(struct dim_stats *curr,
+ struct dim_stats *prev)
+{
+ /* first stat */
+ if (!prev->cpms)
+ return DIM_STATS_SAME;
+
+ if (IS_SIGNIFICANT_DIFF(curr->cpms, prev->cpms))
+ return (curr->cpms > prev->cpms) ? DIM_STATS_BETTER :
+ DIM_STATS_WORSE;
+
+ if (IS_SIGNIFICANT_DIFF(curr->cpe_ratio, prev->cpe_ratio))
+ return (curr->cpe_ratio > prev->cpe_ratio) ? DIM_STATS_BETTER :
+ DIM_STATS_WORSE;
+
+ return DIM_STATS_SAME;
+}
+
+static bool rdma_dim_decision(struct dim_stats *curr_stats, struct dim *dim)
+{
+ int prev_ix = dim->profile_ix;
+ u8 state = dim->tune_state;
+ int stats_res;
+ int step_res;
+
+ if (state != DIM_PARKING_ON_TOP && state != DIM_PARKING_TIRED) {
+ stats_res = rdma_dim_stats_compare(curr_stats,
+ &dim->prev_stats);
+
+ switch (stats_res) {
+ case DIM_STATS_SAME:
+ if (curr_stats->cpe_ratio <= 50 * prev_ix)
+ dim->profile_ix = 0;
+ break;
+ case DIM_STATS_WORSE:
+ dim_turn(dim);
+ fallthrough;
+ case DIM_STATS_BETTER:
+ step_res = rdma_dim_step(dim);
+ if (step_res == DIM_ON_EDGE)
+ dim_turn(dim);
+ break;
+ }
+ }
+
+ dim->prev_stats = *curr_stats;
+
+ return dim->profile_ix != prev_ix;
+}
+
+void rdma_dim(struct dim *dim, u64 completions)
+{
+ struct dim_sample *curr_sample = &dim->measuring_sample;
+ struct dim_stats curr_stats;
+ u32 nevents;
+
+ dim_update_sample_with_comps(curr_sample->event_ctr + 1, 0, 0,
+ curr_sample->comp_ctr + completions,
+ &dim->measuring_sample);
+
+ switch (dim->state) {
+ case DIM_MEASURE_IN_PROGRESS:
+ nevents = curr_sample->event_ctr - dim->start_sample.event_ctr;
+ if (nevents < DIM_NEVENTS)
+ break;
+ if (!dim_calc_stats(&dim->start_sample, curr_sample, &curr_stats))
+ break;
+ if (rdma_dim_decision(&curr_stats, dim)) {
+ dim->state = DIM_APPLY_NEW_PROFILE;
+ schedule_work(&dim->work);
+ break;
+ }
+ fallthrough;
+ case DIM_START_MEASURE:
+ dim->state = DIM_MEASURE_IN_PROGRESS;
+ dim_update_sample_with_comps(curr_sample->event_ctr, 0, 0,
+ curr_sample->comp_ctr,
+ &dim->start_sample);
+ break;
+ case DIM_APPLY_NEW_PROFILE:
+ break;
+ }
+}
+EXPORT_SYMBOL(rdma_dim);