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- /* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
- /* Copyright (c) 2019 Mellanox Technologies. */
- #ifndef DIM_H
- #define DIM_H
- #include <linux/bits.h>
- #include <linux/kernel.h>
- #include <linux/module.h>
- #include <linux/types.h>
- #include <linux/workqueue.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) \
- ((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))
- /**
- * struct dim_cq_moder - 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)
- * @comps: Completion counter
- * @cq_period_mode: CQ period count mode (from CQE/EQE)
- */
- struct dim_cq_moder {
- u16 usec;
- u16 pkts;
- u16 comps;
- u8 cq_period_mode;
- };
- /**
- * struct dim_sample - 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
- * @comp_ctr: Current completion counter
- */
- struct dim_sample {
- ktime_t time;
- u32 pkt_ctr;
- u32 byte_ctr;
- u16 event_ctr;
- u32 comp_ctr;
- };
- /**
- * struct dim_stats - Structure for DIM stats.
- * Used for holding current measured rates.
- *
- * @ppms: Packets per msec
- * @bpms: Bytes per msec
- * @epms: Events per msec
- * @cpms: Completions per msec
- * @cpe_ratio: Ratio of completions to events
- */
- 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 */
- };
- /**
- * struct dim - 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
- * @measuring_sample: A &dim_sample that is used to update the current events
- * @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 - 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 {
- DIM_CQ_PERIOD_MODE_START_FROM_EQE = 0x0,
- DIM_CQ_PERIOD_MODE_START_FROM_CQE = 0x1,
- DIM_CQ_PERIOD_NUM_MODES
- };
- /**
- * enum dim_state - 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_state {
- DIM_START_MEASURE,
- DIM_MEASURE_IN_PROGRESS,
- DIM_APPLY_NEW_PROFILE,
- };
- /**
- * enum dim_tune_state - 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_tune_state {
- DIM_PARKING_ON_TOP,
- DIM_PARKING_TIRED,
- DIM_GOING_RIGHT,
- DIM_GOING_LEFT,
- };
- /**
- * enum dim_stats_state - DIM algorithm statistics states
- *
- * These will determine the verdict of current iteration.
- *
- * @DIM_STATS_WORSE: Current iteration shows worse performance than before
- * @DIM_STATS_SAME: Current iteration shows same performance than before
- * @DIM_STATS_BETTER: Current iteration shows better performance than before
- */
- enum dim_stats_state {
- DIM_STATS_WORSE,
- DIM_STATS_SAME,
- DIM_STATS_BETTER,
- };
- /**
- * enum dim_step_result - 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_step_result {
- 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 altering 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.
- * Returned boolean indicates whether curr_stats are reliable.
- */
- bool 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 given 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_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 */
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