1 /* 2 * QEMU throttling infrastructure 3 * 4 * Copyright (C) Nodalink, EURL. 2013-2014 5 * Copyright (C) Igalia, S.L. 2015 6 * 7 * Authors: 8 * Benoît Canet <benoit.canet@nodalink.com> 9 * Alberto Garcia <berto@igalia.com> 10 * 11 * This program is free software; you can redistribute it and/or 12 * modify it under the terms of the GNU General Public License as 13 * published by the Free Software Foundation; either version 2 or 14 * (at your option) version 3 of the License. 15 * 16 * This program is distributed in the hope that it will be useful, 17 * but WITHOUT ANY WARRANTY; without even the implied warranty of 18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 19 * GNU General Public License for more details. 20 * 21 * You should have received a copy of the GNU General Public License 22 * along with this program; if not, see <http://www.gnu.org/licenses/>. 23 */ 24 25 #ifndef THROTTLE_H 26 #define THROTTLE_H 27 28 #include <stdint.h> 29 #include "qemu-common.h" 30 #include "qemu/timer.h" 31 32 #define THROTTLE_VALUE_MAX 1000000000000000LL 33 34 typedef enum { 35 THROTTLE_BPS_TOTAL, 36 THROTTLE_BPS_READ, 37 THROTTLE_BPS_WRITE, 38 THROTTLE_OPS_TOTAL, 39 THROTTLE_OPS_READ, 40 THROTTLE_OPS_WRITE, 41 BUCKETS_COUNT, 42 } BucketType; 43 44 /* 45 * The max parameter of the leaky bucket throttling algorithm can be used to 46 * allow the guest to do bursts. 47 * The max value is a pool of I/O that the guest can use without being throttled 48 * at all. Throttling is triggered once this pool is empty. 49 */ 50 51 typedef struct LeakyBucket { 52 double avg; /* average goal in units per second */ 53 double max; /* leaky bucket max burst in units */ 54 double level; /* bucket level in units */ 55 } LeakyBucket; 56 57 /* The following structure is used to configure a ThrottleState 58 * It contains a bit of state: the bucket field of the LeakyBucket structure. 59 * However it allows to keep the code clean and the bucket field is reset to 60 * zero at the right time. 61 */ 62 typedef struct ThrottleConfig { 63 LeakyBucket buckets[BUCKETS_COUNT]; /* leaky buckets */ 64 uint64_t op_size; /* size of an operation in bytes */ 65 } ThrottleConfig; 66 67 typedef struct ThrottleState { 68 ThrottleConfig cfg; /* configuration */ 69 int64_t previous_leak; /* timestamp of the last leak done */ 70 } ThrottleState; 71 72 typedef struct ThrottleTimers { 73 QEMUTimer *timers[2]; /* timers used to do the throttling */ 74 QEMUClockType clock_type; /* the clock used */ 75 76 /* Callbacks */ 77 QEMUTimerCB *read_timer_cb; 78 QEMUTimerCB *write_timer_cb; 79 void *timer_opaque; 80 } ThrottleTimers; 81 82 /* operations on single leaky buckets */ 83 void throttle_leak_bucket(LeakyBucket *bkt, int64_t delta); 84 85 int64_t throttle_compute_wait(LeakyBucket *bkt); 86 87 /* expose timer computation function for unit tests */ 88 bool throttle_compute_timer(ThrottleState *ts, 89 bool is_write, 90 int64_t now, 91 int64_t *next_timestamp); 92 93 /* init/destroy cycle */ 94 void throttle_init(ThrottleState *ts); 95 96 void throttle_timers_init(ThrottleTimers *tt, 97 AioContext *aio_context, 98 QEMUClockType clock_type, 99 QEMUTimerCB *read_timer_cb, 100 QEMUTimerCB *write_timer_cb, 101 void *timer_opaque); 102 103 void throttle_timers_destroy(ThrottleTimers *tt); 104 105 void throttle_timers_detach_aio_context(ThrottleTimers *tt); 106 107 void throttle_timers_attach_aio_context(ThrottleTimers *tt, 108 AioContext *new_context); 109 110 bool throttle_timers_are_initialized(ThrottleTimers *tt); 111 112 /* configuration */ 113 bool throttle_enabled(ThrottleConfig *cfg); 114 115 bool throttle_conflicting(ThrottleConfig *cfg); 116 117 bool throttle_is_valid(ThrottleConfig *cfg); 118 119 bool throttle_max_is_missing_limit(ThrottleConfig *cfg); 120 121 void throttle_config(ThrottleState *ts, 122 ThrottleTimers *tt, 123 ThrottleConfig *cfg); 124 125 void throttle_get_config(ThrottleState *ts, ThrottleConfig *cfg); 126 127 /* usage */ 128 bool throttle_schedule_timer(ThrottleState *ts, 129 ThrottleTimers *tt, 130 bool is_write); 131 132 void throttle_account(ThrottleState *ts, bool is_write, uint64_t size); 133 134 #endif 135