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 typedef enum { 33 THROTTLE_BPS_TOTAL, 34 THROTTLE_BPS_READ, 35 THROTTLE_BPS_WRITE, 36 THROTTLE_OPS_TOTAL, 37 THROTTLE_OPS_READ, 38 THROTTLE_OPS_WRITE, 39 BUCKETS_COUNT, 40 } BucketType; 41 42 /* 43 * The max parameter of the leaky bucket throttling algorithm can be used to 44 * allow the guest to do bursts. 45 * The max value is a pool of I/O that the guest can use without being throttled 46 * at all. Throttling is triggered once this pool is empty. 47 */ 48 49 typedef struct LeakyBucket { 50 double avg; /* average goal in units per second */ 51 double max; /* leaky bucket max burst in units */ 52 double level; /* bucket level in units */ 53 } LeakyBucket; 54 55 /* The following structure is used to configure a ThrottleState 56 * It contains a bit of state: the bucket field of the LeakyBucket structure. 57 * However it allows to keep the code clean and the bucket field is reset to 58 * zero at the right time. 59 */ 60 typedef struct ThrottleConfig { 61 LeakyBucket buckets[BUCKETS_COUNT]; /* leaky buckets */ 62 uint64_t op_size; /* size of an operation in bytes */ 63 } ThrottleConfig; 64 65 typedef struct ThrottleState { 66 ThrottleConfig cfg; /* configuration */ 67 int64_t previous_leak; /* timestamp of the last leak done */ 68 } ThrottleState; 69 70 typedef struct ThrottleTimers { 71 QEMUTimer *timers[2]; /* timers used to do the throttling */ 72 QEMUClockType clock_type; /* the clock used */ 73 74 /* Callbacks */ 75 QEMUTimerCB *read_timer_cb; 76 QEMUTimerCB *write_timer_cb; 77 void *timer_opaque; 78 } ThrottleTimers; 79 80 /* operations on single leaky buckets */ 81 void throttle_leak_bucket(LeakyBucket *bkt, int64_t delta); 82 83 int64_t throttle_compute_wait(LeakyBucket *bkt); 84 85 /* expose timer computation function for unit tests */ 86 bool throttle_compute_timer(ThrottleState *ts, 87 bool is_write, 88 int64_t now, 89 int64_t *next_timestamp); 90 91 /* init/destroy cycle */ 92 void throttle_init(ThrottleState *ts); 93 94 void throttle_timers_init(ThrottleTimers *tt, 95 AioContext *aio_context, 96 QEMUClockType clock_type, 97 QEMUTimerCB *read_timer_cb, 98 QEMUTimerCB *write_timer_cb, 99 void *timer_opaque); 100 101 void throttle_timers_destroy(ThrottleTimers *tt); 102 103 void throttle_timers_detach_aio_context(ThrottleTimers *tt); 104 105 void throttle_timers_attach_aio_context(ThrottleTimers *tt, 106 AioContext *new_context); 107 108 bool throttle_timers_are_initialized(ThrottleTimers *tt); 109 110 /* configuration */ 111 bool throttle_enabled(ThrottleConfig *cfg); 112 113 bool throttle_conflicting(ThrottleConfig *cfg); 114 115 bool throttle_is_valid(ThrottleConfig *cfg); 116 117 bool throttle_max_is_missing_limit(ThrottleConfig *cfg); 118 119 void throttle_config(ThrottleState *ts, 120 ThrottleTimers *tt, 121 ThrottleConfig *cfg); 122 123 void throttle_get_config(ThrottleState *ts, ThrottleConfig *cfg); 124 125 /* usage */ 126 bool throttle_schedule_timer(ThrottleState *ts, 127 ThrottleTimers *tt, 128 bool is_write); 129 130 void throttle_account(ThrottleState *ts, bool is_write, uint64_t size); 131 132 #endif 133