Quelle  dim.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
/*
 * Copyright (c) 2019, Mellanox Technologies inc.  All rights reserved.
 */

#include <linux/dim.h>

bool dim_on_top(struct dim *dim)
{
 switch (dim->tune_state) {
 case DIM_PARKING_ON_TOP:
 case DIM_PARKING_TIRED:
  return true;
 case DIM_GOING_RIGHT:
  return (dim->steps_left > 1) && (dim->steps_right == 1);
 default: /* DIM_GOING_LEFT */
  return (dim->steps_right > 1) && (dim->steps_left == 1);
 }
}
EXPORT_SYMBOL(dim_on_top);

void dim_turn(struct dim *dim)
{
 switch (dim->tune_state) {
 case DIM_PARKING_ON_TOP:
 case DIM_PARKING_TIRED:
  break;
 case DIM_GOING_RIGHT:
  dim->tune_state = DIM_GOING_LEFT;
  dim->steps_left = 0;
  break;
 case DIM_GOING_LEFT:
  dim->tune_state = DIM_GOING_RIGHT;
  dim->steps_right = 0;
  break;
 }
}
EXPORT_SYMBOL(dim_turn);

void dim_park_on_top(struct dim *dim)
{
 dim->steps_right  = 0;
 dim->steps_left   = 0;
 dim->tired        = 0;
 dim->tune_state   = DIM_PARKING_ON_TOP;
}
EXPORT_SYMBOL(dim_park_on_top);

void dim_park_tired(struct dim *dim)
{
 dim->steps_right  = 0;
 dim->steps_left   = 0;
 dim->tune_state   = DIM_PARKING_TIRED;
}
EXPORT_SYMBOL(dim_park_tired);

bool dim_calc_stats(const struct dim_sample *start,
      const struct dim_sample *end,
      struct dim_stats *curr_stats)
{
 /* u32 holds up to 71 minutes, should be enough */
 u32 delta_us = ktime_us_delta(end->time, start->time);
 u32 npkts = BIT_GAP(BITS_PER_TYPE(u32), end->pkt_ctr, start->pkt_ctr);
 u32 nbytes = BIT_GAP(BITS_PER_TYPE(u32), end->byte_ctr,
        start->byte_ctr);
 u32 ncomps = BIT_GAP(BITS_PER_TYPE(u32), end->comp_ctr,
        start->comp_ctr);

 if (!delta_us)
  return false;

 curr_stats->ppms = DIV_ROUND_UP(npkts * USEC_PER_MSEC, delta_us);
 curr_stats->bpms = DIV_ROUND_UP(nbytes * USEC_PER_MSEC, delta_us);
 curr_stats->epms = DIV_ROUND_UP(DIM_NEVENTS * USEC_PER_MSEC,
     delta_us);
 curr_stats->cpms = DIV_ROUND_UP(ncomps * USEC_PER_MSEC, delta_us);
 if (curr_stats->epms != 0)
  curr_stats->cpe_ratio = DIV_ROUND_DOWN_ULL(
   curr_stats->cpms * 100, curr_stats->epms);
 else
  curr_stats->cpe_ratio = 0;

 return true;
}
EXPORT_SYMBOL(dim_calc_stats);

MODULE_DESCRIPTION("Dynamic Interrupt Moderation (DIM) library");
MODULE_LICENSE("Dual BSD/GPL");