1 #ifndef __tim_filter_h__ 2 #define __tim_filter_h__ 3 /*- 4 * Copyright (c) 2016-9 Netflix, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 /* 29 * Author: Randall Stewart <rrs@netflix.com> 30 */ 31 32 #include <sys/types.h> 33 #include <machine/param.h> 34 /* 35 * Do not change the size unless you know what you are 36 * doing, the current size of 5 is designed around 37 * the cache-line size for an amd64 processor. Other processors 38 * may need other sizes. 39 */ 40 #define NUM_FILTER_ENTRIES 3 41 42 struct filter_entry { 43 uint64_t value; /* Value */ 44 uint32_t time_up; /* Time updated */ 45 } __packed ; 46 47 struct filter_entry_small { 48 uint32_t value; /* Value */ 49 uint32_t time_up; /* Time updated */ 50 }; 51 52 struct time_filter { 53 uint32_t cur_time_limit; 54 struct filter_entry entries[NUM_FILTER_ENTRIES]; 55 #ifdef _KERNEL 56 } __aligned(CACHE_LINE_SIZE); 57 #else 58 }; 59 #endif 60 struct time_filter_small { 61 uint32_t cur_time_limit; 62 struct filter_entry_small entries[NUM_FILTER_ENTRIES]; 63 }; 64 65 /* 66 * To conserve on space there is a code duplication here (this 67 * is where polymophism would be nice in the kernel). Everything 68 * is duplicated to have a filter with a value of uint32_t instead 69 * of a uint64_t. This saves 20 bytes and the structure size 70 * drops to 44 from 64. The bad part about this is you end 71 * up with two sets of functions. The xxx_small() access 72 * the uint32_t value's where the xxx() the uint64_t values. 73 * This forces the user to keep straight which type of structure 74 * they allocated and which call they need to make. crossing 75 * over calls will create either invalid memory references or 76 * very bad results :) 77 */ 78 79 #define FILTER_TYPE_MIN 1 80 #define FILTER_TYPE_MAX 2 81 82 #ifdef _KERNEL 83 int setup_time_filter(struct time_filter *tf, int fil_type, uint32_t time_len); 84 void reset_time(struct time_filter *tf, uint32_t time_len); 85 void forward_filter_clock(struct time_filter *tf, uint32_t ticks_forward); 86 void tick_filter_clock(struct time_filter *tf, uint32_t now); 87 uint32_t apply_filter_min(struct time_filter *tf, uint64_t value, uint32_t now); 88 uint32_t apply_filter_max(struct time_filter *tf, uint64_t value, uint32_t now); 89 void filter_reduce_by(struct time_filter *tf, uint64_t reduce_by, uint32_t now); 90 void filter_increase_by(struct time_filter *tf, uint64_t incr_by, uint32_t now); 91 static uint64_t inline 92 get_filter_value(struct time_filter *tf) 93 { 94 return(tf->entries[0].value); 95 } 96 97 static uint32_t inline 98 get_cur_timelim(struct time_filter *tf) 99 { 100 return(tf->cur_time_limit); 101 } 102 103 int setup_time_filter_small(struct time_filter_small *tf, 104 int fil_type, uint32_t time_len); 105 void reset_time_small(struct time_filter_small *tf, uint32_t time_len); 106 void forward_filter_clock_small(struct time_filter_small *tf, 107 uint32_t ticks_forward); 108 void tick_filter_clock_small(struct time_filter_small *tf, uint32_t now); 109 uint32_t apply_filter_min_small(struct time_filter_small *tf, 110 uint32_t value, uint32_t now); 111 uint32_t apply_filter_max_small(struct time_filter_small *tf, 112 uint32_t value, uint32_t now); 113 void filter_reduce_by_small(struct time_filter_small *tf, 114 uint32_t reduce_by, uint32_t now); 115 void filter_increase_by_small(struct time_filter_small *tf, 116 uint32_t incr_by, uint32_t now); 117 static uint64_t inline 118 get_filter_value_small(struct time_filter_small *tf) 119 { 120 return(tf->entries[0].value); 121 } 122 123 static uint32_t inline 124 get_cur_timelim_small(struct time_filter_small *tf) 125 { 126 return(tf->cur_time_limit); 127 } 128 129 #endif 130 #endif 131