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