https://github.com/torvalds/linux
Tip revision: cd6c84d8f0cdc911df435bb075ba22ce3c605b07 authored by Linus Torvalds on 26 May 2019, 23:49:19 UTC
Linux 5.2-rc2
Linux 5.2-rc2
Tip revision: cd6c84d
net_dim.h
/*
* Copyright (c) 2016, Mellanox Technologies. All rights reserved.
* Copyright (c) 2017-2018, Broadcom Limited. All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2, available from the file
* COPYING in the main directory of this source tree, or the
* OpenIB.org BSD license below:
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#ifndef NET_DIM_H
#define NET_DIM_H
#include <linux/module.h>
struct net_dim_cq_moder {
u16 usec;
u16 pkts;
u8 cq_period_mode;
};
struct net_dim_sample {
ktime_t time;
u32 pkt_ctr;
u32 byte_ctr;
u16 event_ctr;
};
struct net_dim_stats {
int ppms; /* packets per msec */
int bpms; /* bytes per msec */
int epms; /* events per msec */
};
struct net_dim { /* Adaptive Moderation */
u8 state;
struct net_dim_stats prev_stats;
struct net_dim_sample start_sample;
struct work_struct work;
u8 profile_ix;
u8 mode;
u8 tune_state;
u8 steps_right;
u8 steps_left;
u8 tired;
};
enum {
NET_DIM_CQ_PERIOD_MODE_START_FROM_EQE = 0x0,
NET_DIM_CQ_PERIOD_MODE_START_FROM_CQE = 0x1,
NET_DIM_CQ_PERIOD_NUM_MODES
};
/* Adaptive moderation logic */
enum {
NET_DIM_START_MEASURE,
NET_DIM_MEASURE_IN_PROGRESS,
NET_DIM_APPLY_NEW_PROFILE,
};
enum {
NET_DIM_PARKING_ON_TOP,
NET_DIM_PARKING_TIRED,
NET_DIM_GOING_RIGHT,
NET_DIM_GOING_LEFT,
};
enum {
NET_DIM_STATS_WORSE,
NET_DIM_STATS_SAME,
NET_DIM_STATS_BETTER,
};
enum {
NET_DIM_STEPPED,
NET_DIM_TOO_TIRED,
NET_DIM_ON_EDGE,
};
#define NET_DIM_PARAMS_NUM_PROFILES 5
/* Adaptive moderation profiles */
#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
/* All profiles sizes must be NET_PARAMS_DIM_NUM_PROFILES */
#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 net_dim_cq_moder
rx_profile[NET_DIM_CQ_PERIOD_NUM_MODES][NET_DIM_PARAMS_NUM_PROFILES] = {
NET_DIM_RX_EQE_PROFILES,
NET_DIM_RX_CQE_PROFILES,
};
static const struct net_dim_cq_moder
tx_profile[NET_DIM_CQ_PERIOD_NUM_MODES][NET_DIM_PARAMS_NUM_PROFILES] = {
NET_DIM_TX_EQE_PROFILES,
NET_DIM_TX_CQE_PROFILES,
};
static inline struct net_dim_cq_moder
net_dim_get_rx_moderation(u8 cq_period_mode, int ix)
{
struct net_dim_cq_moder cq_moder = rx_profile[cq_period_mode][ix];
cq_moder.cq_period_mode = cq_period_mode;
return cq_moder;
}
static inline struct net_dim_cq_moder
net_dim_get_def_rx_moderation(u8 cq_period_mode)
{
u8 profile_ix = cq_period_mode == NET_DIM_CQ_PERIOD_MODE_START_FROM_CQE ?
NET_DIM_DEF_PROFILE_CQE : NET_DIM_DEF_PROFILE_EQE;
return net_dim_get_rx_moderation(cq_period_mode, profile_ix);
}
static inline struct net_dim_cq_moder
net_dim_get_tx_moderation(u8 cq_period_mode, int ix)
{
struct net_dim_cq_moder cq_moder = tx_profile[cq_period_mode][ix];
cq_moder.cq_period_mode = cq_period_mode;
return cq_moder;
}
static inline struct net_dim_cq_moder
net_dim_get_def_tx_moderation(u8 cq_period_mode)
{
u8 profile_ix = cq_period_mode == NET_DIM_CQ_PERIOD_MODE_START_FROM_CQE ?
NET_DIM_DEF_PROFILE_CQE : NET_DIM_DEF_PROFILE_EQE;
return net_dim_get_tx_moderation(cq_period_mode, profile_ix);
}
static inline bool net_dim_on_top(struct net_dim *dim)
{
switch (dim->tune_state) {
case NET_DIM_PARKING_ON_TOP:
case NET_DIM_PARKING_TIRED:
return true;
case NET_DIM_GOING_RIGHT:
return (dim->steps_left > 1) && (dim->steps_right == 1);
default: /* NET_DIM_GOING_LEFT */
return (dim->steps_right > 1) && (dim->steps_left == 1);
}
}
static inline void net_dim_turn(struct net_dim *dim)
{
switch (dim->tune_state) {
case NET_DIM_PARKING_ON_TOP:
case NET_DIM_PARKING_TIRED:
break;
case NET_DIM_GOING_RIGHT:
dim->tune_state = NET_DIM_GOING_LEFT;
dim->steps_left = 0;
break;
case NET_DIM_GOING_LEFT:
dim->tune_state = NET_DIM_GOING_RIGHT;
dim->steps_right = 0;
break;
}
}
static inline int net_dim_step(struct net_dim *dim)
{
if (dim->tired == (NET_DIM_PARAMS_NUM_PROFILES * 2))
return NET_DIM_TOO_TIRED;
switch (dim->tune_state) {
case NET_DIM_PARKING_ON_TOP:
case NET_DIM_PARKING_TIRED:
break;
case NET_DIM_GOING_RIGHT:
if (dim->profile_ix == (NET_DIM_PARAMS_NUM_PROFILES - 1))
return NET_DIM_ON_EDGE;
dim->profile_ix++;
dim->steps_right++;
break;
case NET_DIM_GOING_LEFT:
if (dim->profile_ix == 0)
return NET_DIM_ON_EDGE;
dim->profile_ix--;
dim->steps_left++;
break;
}
dim->tired++;
return NET_DIM_STEPPED;
}
static inline void net_dim_park_on_top(struct net_dim *dim)
{
dim->steps_right = 0;
dim->steps_left = 0;
dim->tired = 0;
dim->tune_state = NET_DIM_PARKING_ON_TOP;
}
static inline void net_dim_park_tired(struct net_dim *dim)
{
dim->steps_right = 0;
dim->steps_left = 0;
dim->tune_state = NET_DIM_PARKING_TIRED;
}
static inline void net_dim_exit_parking(struct net_dim *dim)
{
dim->tune_state = dim->profile_ix ? NET_DIM_GOING_LEFT :
NET_DIM_GOING_RIGHT;
net_dim_step(dim);
}
#define IS_SIGNIFICANT_DIFF(val, ref) \
(((100UL * abs((val) - (ref))) / (ref)) > 10) /* more than 10% difference */
static inline int net_dim_stats_compare(struct net_dim_stats *curr,
struct net_dim_stats *prev)
{
if (!prev->bpms)
return curr->bpms ? NET_DIM_STATS_BETTER :
NET_DIM_STATS_SAME;
if (IS_SIGNIFICANT_DIFF(curr->bpms, prev->bpms))
return (curr->bpms > prev->bpms) ? NET_DIM_STATS_BETTER :
NET_DIM_STATS_WORSE;
if (!prev->ppms)
return curr->ppms ? NET_DIM_STATS_BETTER :
NET_DIM_STATS_SAME;
if (IS_SIGNIFICANT_DIFF(curr->ppms, prev->ppms))
return (curr->ppms > prev->ppms) ? NET_DIM_STATS_BETTER :
NET_DIM_STATS_WORSE;
if (!prev->epms)
return NET_DIM_STATS_SAME;
if (IS_SIGNIFICANT_DIFF(curr->epms, prev->epms))
return (curr->epms < prev->epms) ? NET_DIM_STATS_BETTER :
NET_DIM_STATS_WORSE;
return NET_DIM_STATS_SAME;
}
static inline bool net_dim_decision(struct net_dim_stats *curr_stats,
struct net_dim *dim)
{
int prev_state = dim->tune_state;
int prev_ix = dim->profile_ix;
int stats_res;
int step_res;
switch (dim->tune_state) {
case NET_DIM_PARKING_ON_TOP:
stats_res = net_dim_stats_compare(curr_stats, &dim->prev_stats);
if (stats_res != NET_DIM_STATS_SAME)
net_dim_exit_parking(dim);
break;
case NET_DIM_PARKING_TIRED:
dim->tired--;
if (!dim->tired)
net_dim_exit_parking(dim);
break;
case NET_DIM_GOING_RIGHT:
case NET_DIM_GOING_LEFT:
stats_res = net_dim_stats_compare(curr_stats, &dim->prev_stats);
if (stats_res != NET_DIM_STATS_BETTER)
net_dim_turn(dim);
if (net_dim_on_top(dim)) {
net_dim_park_on_top(dim);
break;
}
step_res = net_dim_step(dim);
switch (step_res) {
case NET_DIM_ON_EDGE:
net_dim_park_on_top(dim);
break;
case NET_DIM_TOO_TIRED:
net_dim_park_tired(dim);
break;
}
break;
}
if ((prev_state != NET_DIM_PARKING_ON_TOP) ||
(dim->tune_state != NET_DIM_PARKING_ON_TOP))
dim->prev_stats = *curr_stats;
return dim->profile_ix != prev_ix;
}
static inline void net_dim_sample(u16 event_ctr,
u64 packets,
u64 bytes,
struct net_dim_sample *s)
{
s->time = ktime_get();
s->pkt_ctr = packets;
s->byte_ctr = bytes;
s->event_ctr = event_ctr;
}
#define NET_DIM_NEVENTS 64
#define BIT_GAP(bits, end, start) ((((end) - (start)) + BIT_ULL(bits)) & (BIT_ULL(bits) - 1))
static inline void net_dim_calc_stats(struct net_dim_sample *start,
struct net_dim_sample *end,
struct net_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);
if (!delta_us)
return;
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(NET_DIM_NEVENTS * USEC_PER_MSEC,
delta_us);
}
static inline void net_dim(struct net_dim *dim,
struct net_dim_sample end_sample)
{
struct net_dim_stats curr_stats;
u16 nevents;
switch (dim->state) {
case NET_DIM_MEASURE_IN_PROGRESS:
nevents = BIT_GAP(BITS_PER_TYPE(u16),
end_sample.event_ctr,
dim->start_sample.event_ctr);
if (nevents < NET_DIM_NEVENTS)
break;
net_dim_calc_stats(&dim->start_sample, &end_sample,
&curr_stats);
if (net_dim_decision(&curr_stats, dim)) {
dim->state = NET_DIM_APPLY_NEW_PROFILE;
schedule_work(&dim->work);
break;
}
/* fall through */
case NET_DIM_START_MEASURE:
net_dim_sample(end_sample.event_ctr, end_sample.pkt_ctr, end_sample.byte_ctr,
&dim->start_sample);
dim->state = NET_DIM_MEASURE_IN_PROGRESS;
break;
case NET_DIM_APPLY_NEW_PROFILE:
break;
}
}
#endif /* NET_DIM_H */