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336 lines
9.1 KiB
336 lines
9.1 KiB
/* 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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*/ |
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void 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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