1 files changed, 389 insertions, 0 deletions

diff --git a/include/linux/dim.h b/include/linux/dim.h
new file mode 100644
index 000000000000..d3a0fbfff2bb
--- /dev/null
+++ b/include/linux/dim.h
@@ -0,0 +1,389 @@
+/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
+/* Copyright (c) 2019 Mellanox Technologies. */
+
+#ifndef DIM_H
+#define DIM_H
+
+#include <linux/module.h>
+
+/**
+ * Number of events between DIM iterations.
+ * Causes a moderation of the algorithm run.
+ */
+#define DIM_NEVENTS 64
+
+/**
+ * Is a difference between values justifies taking an action.
+ * We consider 10% difference as significant.
+ */
+#define IS_SIGNIFICANT_DIFF(val, ref) \
+        (((100UL * abs((val) - (ref))) / (ref)) > 10)
+
+/**
+ * Calculate the gap between two values.
+ * Take wrap-around and variable size into consideration.
+ */
+#define BIT_GAP(bits, end, start) ((((end) - (start)) + BIT_ULL(bits)) \
+                & (BIT_ULL(bits) - 1))
+
+/**
+ * Structure for CQ moderation values.
+ * Used for communications between DIM and its consumer.
+ *
+ * @usec: CQ timer suggestion (by DIM)
+ * @pkts: CQ packet counter suggestion (by DIM)
+ * @cq_period_mode: CQ priod count mode (from CQE/EQE)
+ */
+struct dim_cq_moder {
+        u16 usec;
+        u16 pkts;
+        u16 comps;
+        u8 cq_period_mode;
+};
+
+/**
+ * Structure for DIM sample data.
+ * Used for communications between DIM and its consumer.
+ *
+ * @time: Sample timestamp
+ * @pkt_ctr: Number of packets
+ * @byte_ctr: Number of bytes
+ * @event_ctr: Number of events
+ */
+struct dim_sample {
+        ktime_t time;
+        u32 pkt_ctr;
+        u32 byte_ctr;
+        u16 event_ctr;
+        u32 comp_ctr;
+};
+
+/**
+ * Structure for DIM stats.
+ * Used for holding current measured rates.
+ *
+ * @ppms: Packets per msec
+ * @bpms: Bytes per msec
+ * @epms: Events per msec
+ */
+struct dim_stats {
+        int ppms; /* packets per msec */
+        int bpms; /* bytes per msec */
+        int epms; /* events per msec */
+        int cpms; /* completions per msec */
+        int cpe_ratio; /* ratio of completions to events */
+};
+
+/**
+ * Main structure for dynamic interrupt moderation (DIM).
+ * Used for holding all information about a specific DIM instance.
+ *
+ * @state: Algorithm state (see below)
+ * @prev_stats: Measured rates from previous iteration (for comparison)
+ * @start_sample: Sampled data at start of current iteration
+ * @work: Work to perform on action required
+ * @priv: A pointer to the struct that points to dim
+ * @profile_ix: Current moderation profile
+ * @mode: CQ period count mode
+ * @tune_state: Algorithm tuning state (see below)
+ * @steps_right: Number of steps taken towards higher moderation
+ * @steps_left: Number of steps taken towards lower moderation
+ * @tired: Parking depth counter
+ */
+struct dim {
+        u8 state;
+        struct dim_stats prev_stats;
+        struct dim_sample start_sample;
+        struct dim_sample measuring_sample;
+        struct work_struct work;
+        void *priv;
+        u8 profile_ix;
+        u8 mode;
+        u8 tune_state;
+        u8 steps_right;
+        u8 steps_left;
+        u8 tired;
+};
+
+/**
+ * enum dim_cq_period_mode
+ *
+ * These are the modes for CQ period count.
+ *
+ * @DIM_CQ_PERIOD_MODE_START_FROM_EQE: Start counting from EQE
+ * @DIM_CQ_PERIOD_MODE_START_FROM_CQE: Start counting from CQE (implies timer reset)
+ * @DIM_CQ_PERIOD_NUM_MODES: Number of modes
+ */
+enum {
+        DIM_CQ_PERIOD_MODE_START_FROM_EQE = 0x0,
+        DIM_CQ_PERIOD_MODE_START_FROM_CQE = 0x1,
+        DIM_CQ_PERIOD_NUM_MODES
+};
+
+/**
+ * enum dim_state
+ *
+ * These are the DIM algorithm states.
+ * These will determine if the algorithm is in a valid state to start an iteration.
+ *
+ * @DIM_START_MEASURE: This is the first iteration (also after applying a new profile)
+ * @DIM_MEASURE_IN_PROGRESS: Algorithm is already in progress - check if
+ * need to perform an action
+ * @DIM_APPLY_NEW_PROFILE: DIM consumer is currently applying a profile - no need to measure
+ */
+enum {
+        DIM_START_MEASURE,
+        DIM_MEASURE_IN_PROGRESS,
+        DIM_APPLY_NEW_PROFILE,
+};
+
+/**
+ * enum dim_tune_state
+ *
+ * These are the DIM algorithm tune states.
+ * These will determine which action the algorithm should perform.
+ *
+ * @DIM_PARKING_ON_TOP: Algorithm found a local top point - exit on significant difference
+ * @DIM_PARKING_TIRED: Algorithm found a deep top point - don't exit if tired > 0
+ * @DIM_GOING_RIGHT: Algorithm is currently trying higher moderation levels
+ * @DIM_GOING_LEFT: Algorithm is currently trying lower moderation levels
+ */
+enum {
+        DIM_PARKING_ON_TOP,
+        DIM_PARKING_TIRED,
+        DIM_GOING_RIGHT,
+        DIM_GOING_LEFT,
+};
+
+/**
+ * enum dim_stats_state
+ *
+ * These are the DIM algorithm statistics states.
+ * These will determine the verdict of current iteration.
+ *
+ * @DIM_STATS_WORSE: Current iteration shows worse performance than before
+ * @DIM_STATS_WORSE: Current iteration shows same performance than before
+ * @DIM_STATS_WORSE: Current iteration shows better performance than before
+ */
+enum {
+        DIM_STATS_WORSE,
+        DIM_STATS_SAME,
+        DIM_STATS_BETTER,
+};
+
+/**
+ * enum dim_step_result
+ *
+ * These are the DIM algorithm step results.
+ * These describe the result of a step.
+ *
+ * @DIM_STEPPED: Performed a regular step
+ * @DIM_TOO_TIRED: Same kind of step was done multiple times - should go to
+ * tired parking
+ * @DIM_ON_EDGE: Stepped to the most left/right profile
+ */
+enum {
+        DIM_STEPPED,
+        DIM_TOO_TIRED,
+        DIM_ON_EDGE,
+};
+
+/**
+ *      dim_on_top - check if current state is a good place to stop (top location)
+ *      @dim: DIM context
+ *
+ * Check if current profile is a good place to park at.
+ * This will result in reducing the DIM checks frequency as we assume we
+ * shouldn't probably change profiles, unless traffic pattern wasn't changed.
+ */
+bool dim_on_top(struct dim *dim);
+
+/**
+ *      dim_turn - change profile alterning direction
+ *      @dim: DIM context
+ *
+ * Go left if we were going right and vice-versa.
+ * Do nothing if currently parking.
+ */
+void dim_turn(struct dim *dim);
+
+/**
+ *      dim_park_on_top - enter a parking state on a top location
+ *      @dim: DIM context
+ *
+ * Enter parking state.
+ * Clear all movement history.
+ */
+void dim_park_on_top(struct dim *dim);
+
+/**
+ *      dim_park_tired - enter a tired parking state
+ *      @dim: DIM context
+ *
+ * Enter parking state.
+ * Clear all movement history and cause DIM checks frequency to reduce.
+ */
+void dim_park_tired(struct dim *dim);
+
+/**
+ *      dim_calc_stats - calculate the difference between two samples
+ *      @start: start sample
+ *      @end: end sample
+ *      @curr_stats: delta between samples
+ *
+ * Calculate the delta between two samples (in data rates).
+ * Takes into consideration counter wrap-around.
+ */
+void dim_calc_stats(struct dim_sample *start, struct dim_sample *end,
+                    struct dim_stats *curr_stats);
+
+/**
+ *      dim_update_sample - set a sample's fields with give values
+ *      @event_ctr: number of events to set
+ *      @packets: number of packets to set
+ *      @bytes: number of bytes to set
+ *      @s: DIM sample
+ */
+static inline void
+dim_update_sample(u16 event_ctr, u64 packets, u64 bytes, struct dim_sample *s)
+{
+        s->time      = ktime_get();
+        s->pkt_ctr   = packets;
+        s->byte_ctr  = bytes;
+        s->event_ctr = event_ctr;
+}
+
+/**
+ *      dim_update_sample_with_comps - set a sample's fields with given
+ *      values including the completion parameter
+ *      @event_ctr: number of events to set
+ *      @packets: number of packets to set
+ *      @bytes: number of bytes to set
+ *      @comps: number of completions to set
+ *      @s: DIM sample
+ */
+static inline void
+dim_update_sample_with_comps(u16 event_ctr, u64 packets, u64 bytes, u64 comps,
+                             struct dim_sample *s)
+{
+        dim_update_sample(event_ctr, packets, bytes, s);
+        s->comp_ctr = comps;
+}
+
+/* Net DIM */
+
+/*
+ * Net DIM profiles:
+ *        There are different set of profiles for each CQ period mode.
+ *        There are different set of profiles for RX/TX CQs.
+ *        Each profile size must be of NET_DIM_PARAMS_NUM_PROFILES
+ */
+#define NET_DIM_PARAMS_NUM_PROFILES 5
+#define NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE 256
+#define NET_DIM_DEFAULT_TX_CQ_MODERATION_PKTS_FROM_EQE 128
+#define NET_DIM_DEF_PROFILE_CQE 1
+#define NET_DIM_DEF_PROFILE_EQE 1
+
+#define NET_DIM_RX_EQE_PROFILES { \
+        {1,   NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
+        {8,   NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
+        {64,  NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
+        {128, NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
+        {256, NET_DIM_DEFAULT_RX_CQ_MODERATION_PKTS_FROM_EQE}, \
+}
+
+#define NET_DIM_RX_CQE_PROFILES { \
+        {2,  256},             \
+        {8,  128},             \
+        {16, 64},              \
+        {32, 64},              \
+        {64, 64}               \
+}
+
+#define NET_DIM_TX_EQE_PROFILES { \
+        {1,   NET_DIM_DEFAULT_TX_CQ_MODERATION_PKTS_FROM_EQE},  \
+        {8,   NET_DIM_DEFAULT_TX_CQ_MODERATION_PKTS_FROM_EQE},  \
+        {32,  NET_DIM_DEFAULT_TX_CQ_MODERATION_PKTS_FROM_EQE},  \
+        {64,  NET_DIM_DEFAULT_TX_CQ_MODERATION_PKTS_FROM_EQE},  \
+        {128, NET_DIM_DEFAULT_TX_CQ_MODERATION_PKTS_FROM_EQE}   \
+}
+
+#define NET_DIM_TX_CQE_PROFILES { \
+        {5,  128},  \
+        {8,  64},  \
+        {16, 32},  \
+        {32, 32},  \
+        {64, 32}   \
+}
+
+static const struct dim_cq_moder
+rx_profile[DIM_CQ_PERIOD_NUM_MODES][NET_DIM_PARAMS_NUM_PROFILES] = {
+        NET_DIM_RX_EQE_PROFILES,
+        NET_DIM_RX_CQE_PROFILES,
+};
+
+static const struct dim_cq_moder
+tx_profile[DIM_CQ_PERIOD_NUM_MODES][NET_DIM_PARAMS_NUM_PROFILES] = {
+        NET_DIM_TX_EQE_PROFILES,
+        NET_DIM_TX_CQE_PROFILES,
+};
+
+/**
+ *      net_dim_get_rx_moderation - provide a CQ moderation object for the given RX profile
+ *      @cq_period_mode: CQ period mode
+ *      @ix: Profile index
+ */
+struct dim_cq_moder net_dim_get_rx_moderation(u8 cq_period_mode, int ix);
+
+/**
+ *      net_dim_get_def_rx_moderation - provide the default RX moderation
+ *      @cq_period_mode: CQ period mode
+ */
+struct dim_cq_moder net_dim_get_def_rx_moderation(u8 cq_period_mode);
+
+/**
+ *      net_dim_get_tx_moderation - provide a CQ moderation object for the given TX profile
+ *      @cq_period_mode: CQ period mode
+ *      @ix: Profile index
+ */
+struct dim_cq_moder net_dim_get_tx_moderation(u8 cq_period_mode, int ix);
+
+/**
+ *      net_dim_get_def_tx_moderation - provide the default TX moderation
+ *      @cq_period_mode: CQ period mode
+ */
+struct dim_cq_moder net_dim_get_def_tx_moderation(u8 cq_period_mode);
+
+/**
+ *      net_dim - main DIM algorithm entry point
+ *      @dim: DIM instance information
+ *      @end_sample: Current data measurement
+ *
+ * Called by the consumer.
+ * This is the main logic of the algorithm, where data is processed in order to decide on next
+ * required action.
+ */
+void net_dim(struct dim *dim, struct dim_sample end_sample);
+
+/* RDMA DIM */
+
+/*
+ * RDMA DIM profile:
+ * profile size must be of RDMA_DIM_PARAMS_NUM_PROFILES.
+ */
+#define RDMA_DIM_PARAMS_NUM_PROFILES 9
+#define RDMA_DIM_START_PROFILE 0
+
+/**
+ * rdma_dim - Runs the adaptive moderation.
+ * @dim: The moderation struct.
+ * @completions: The number of completions collected in this round.
+ *
+ * Each call to rdma_dim takes the latest amount of completions that
+ * have been collected and counts them as a new event.
+ * Once enough events have been collected the algorithm decides a new
+ * moderation level.
+ */
+void rdma_dim(struct dim *dim, u64 completions);
+
+#endif /* DIM_H */