1 /* 2 * (c) Copyright 1990-1996 OPEN SOFTWARE FOUNDATION, INC. 3 * (c) Copyright 1990-1996 HEWLETT-PACKARD COMPANY 4 * (c) Copyright 1990-1996 DIGITAL EQUIPMENT CORPORATION 5 * (c) Copyright 1991, 1992 Siemens-Nixdorf Information Systems 6 * To anyone who acknowledges that this file is provided "AS IS" without 7 * any express or implied warranty: permission to use, copy, modify, and 8 * distribute this file for any purpose is hereby granted without fee, 9 * provided that the above copyright notices and this notice appears in 10 * all source code copies, and that none of the names listed above be used 11 * in advertising or publicity pertaining to distribution of the software 12 * without specific, written prior permission. None of these organizations 13 * makes any representations about the suitability of this software for 14 * any purpose. 15 */ 16 /* 17 * Header file for priority scheduling 18 */ 19 20 21 #ifndef CMA_SCHED 22 #define CMA_SCHED 23 24 /* 25 * INCLUDE FILES 26 */ 27 28 /* 29 * CONSTANTS AND MACROS 30 */ 31 32 /* 33 * Scaling factor for integer priority calculations 34 */ 35 #define cma__c_prio_scale 8 36 37 #if _CMA_VENDOR_ == _CMA__APOLLO 38 /* 39 * FIX-ME: Apollo cc 6.8 blows contant folded "<<" and ">>" 40 */ 41 # define cma__scale_up(exp) ((exp) * 256) 42 # define cma__scale_dn(exp) ((exp) / 256) 43 #else 44 # define cma__scale_up(exp) ((exp) << cma__c_prio_scale) 45 # define cma__scale_dn(exp) ((exp) >> cma__c_prio_scale) 46 #endif 47 48 49 /* 50 * Min. num. of ticks between self-adjustments for priority adjusting policies. 51 */ 52 #define cma__c_prio_interval 10 53 54 55 /* 56 * Number of queues in each class of queues 57 */ 58 #define cma__c_prio_n_id 1 /* Very-low-priority class threads */ 59 #define cma__c_prio_n_bg 8 /* Background class threads */ 60 #define cma__c_prio_n_0 1 /* Very low priority throughput quartile */ 61 #define cma__c_prio_n_1 2 /* Low priority throughput quartile */ 62 #define cma__c_prio_n_2 3 /* Medium priority throughput quartile */ 63 #define cma__c_prio_n_3 4 /* High priority throughput quartile */ 64 #define cma__c_prio_n_rt 1 /* Real Time priority queues */ 65 66 /* 67 * Number of queues to skip (offset) to get to the queues in this section of LA 68 */ 69 #define cma__c_prio_o_id 0 70 #define cma__c_prio_o_bg cma__c_prio_o_id + cma__c_prio_n_id 71 #define cma__c_prio_o_0 cma__c_prio_o_bg + cma__c_prio_n_bg 72 #define cma__c_prio_o_1 cma__c_prio_o_0 + cma__c_prio_n_0 73 #define cma__c_prio_o_2 cma__c_prio_o_1 + cma__c_prio_n_1 74 #define cma__c_prio_o_3 cma__c_prio_o_2 + cma__c_prio_n_2 75 #define cma__c_prio_o_rt cma__c_prio_o_3 + cma__c_prio_n_3 76 77 /* 78 * Ada_low: These threads are queued in the background queues, thus there 79 * must be enough queues to allow one queue for each Ada priority below the 80 * Ada default. 81 */ 82 #define cma__c_prio_o_al cma__c_prio_o_bg 83 84 /* 85 * Total number of ready queues, for declaration purposes 86 */ 87 #define cma__c_prio_n_tot \ 88 cma__c_prio_n_id + cma__c_prio_n_bg + cma__c_prio_n_rt \ 89 + cma__c_prio_n_0 + cma__c_prio_n_1 + cma__c_prio_n_2 + cma__c_prio_n_3 90 91 /* 92 * Formulae for determining a thread's priority. Variable priorities (such 93 * as foreground and background) are scaled values. 94 */ 95 #define cma__sched_priority(tcb) \ 96 ((tcb)->sched.class == cma__c_class_fore ? cma__sched_prio_fore (tcb) \ 97 :((tcb)->sched.class == cma__c_class_back ? cma__sched_prio_back (tcb) \ 98 :((tcb)->sched.class == cma__c_class_rt ? cma__sched_prio_rt (tcb) \ 99 :((tcb)->sched.class == cma__c_class_idle ? cma__sched_prio_idle (tcb) \ 100 :(cma__bugcheck ("cma__sched_priority: unrecognized class"), 0) )))) 101 102 #define cma__sched_prio_fore(tcb) cma__sched_prio_fore_var (tcb) 103 #define cma__sched_prio_back(tcb) ((tcb)->sched.fixed_prio \ 104 ? cma__sched_prio_back_fix (tcb) : cma__sched_prio_back_var (tcb) ) 105 #define cma__sched_prio_rt(tcb) ((tcb)->sched.priority) 106 #define cma__sched_prio_idle(tcb) ((tcb)->sched.priority) 107 108 #define cma__sched_prio_back_fix(tcb) \ 109 (cma__g_prio_bg_min + (cma__g_prio_bg_max - cma__g_prio_bg_min) \ 110 * ((tcb)->sched.priority + cma__c_prio_o_al - cma__c_prio_o_bg) \ 111 / cma__c_prio_n_bg) 112 113 /* 114 * FIX-ME: Enable after modeling (if we like it) 115 */ 116 #if 1 117 # define cma__sched_prio_fore_var(tcb) \ 118 ((cma__g_prio_fg_max + cma__g_prio_fg_min)/2) 119 # define cma__sched_prio_back_var(tcb) \ 120 ((cma__g_prio_bg_max + cma__g_prio_bg_min)/2) 121 #else 122 # define cma__sched_prio_back_var(tcb) cma__sched_prio_fore_var (tcb) 123 124 # if 1 125 /* 126 * Re-scale, since the division removes the scale factor. 127 * Scale and multiply before dividing to avoid loss of precision. 128 */ 129 # define cma__sched_prio_fore_var(tcb) \ 130 ((cma__g_vp_count * cma__scale_up((tcb)->sched.tot_time)) \ 131 / (tcb)->sched.cpu_time) 132 # else 133 /* 134 * Re-scale, since the division removes the scale factor. 135 * Scale and multiply before dividing to avoid loss of precision. 136 * Left shift the numerator to multiply by two. 137 */ 138 # define cma__sched_prio_fore_var(tcb) \ 139 (((cma__g_vp_count * cma__scale_up((tcb)->sched.tot_time) \ 140 * (tcb)->sched.priority * cma__g_init_frac_sum) << 1) \ 141 / ((tcb)->sched.cpu_time * (tcb)->sched.priority * cma__g_init_frac_sum \ 142 + (tcb)->sched.tot_time)) 143 # endif 144 #endif 145 146 /* 147 * Update weighted-averaged, scaled tick counters 148 */ 149 #define cma__sched_update_time(ave, new) \ 150 (ave) = (ave) - ((cma__scale_dn((ave)) - (new)) << (cma__c_prio_scale - 4)) 151 152 #define cma__sched_parameterize(tcb, policy) { \ 153 switch (policy) { \ 154 case cma_c_sched_fifo : { \ 155 (tcb)->sched.rtb = cma_c_true; \ 156 (tcb)->sched.spp = cma_c_true; \ 157 (tcb)->sched.fixed_prio = cma_c_true; \ 158 (tcb)->sched.class = cma__c_class_rt; \ 159 break; \ 160 } \ 161 case cma_c_sched_rr : { \ 162 (tcb)->sched.rtb = cma_c_false; \ 163 (tcb)->sched.spp = cma_c_true; \ 164 (tcb)->sched.fixed_prio = cma_c_true; \ 165 (tcb)->sched.class = cma__c_class_rt; \ 166 break; \ 167 } \ 168 case cma_c_sched_throughput : { \ 169 (tcb)->sched.rtb = cma_c_false; \ 170 (tcb)->sched.spp = cma_c_false; \ 171 (tcb)->sched.fixed_prio = cma_c_false; \ 172 (tcb)->sched.class = cma__c_class_fore; \ 173 break; \ 174 } \ 175 case cma_c_sched_background : { \ 176 (tcb)->sched.rtb = cma_c_false; \ 177 (tcb)->sched.spp = cma_c_false; \ 178 (tcb)->sched.fixed_prio = cma_c_false; \ 179 (tcb)->sched.class = cma__c_class_back; \ 180 break; \ 181 } \ 182 case cma_c_sched_ada_low : { \ 183 (tcb)->sched.rtb = cma_c_false; \ 184 (tcb)->sched.spp = cma_c_true; \ 185 (tcb)->sched.fixed_prio = cma_c_true; \ 186 (tcb)->sched.class = cma__c_class_back; \ 187 break; \ 188 } \ 189 case cma_c_sched_idle : { \ 190 (tcb)->sched.rtb = cma_c_false; \ 191 (tcb)->sched.spp = cma_c_false; \ 192 (tcb)->sched.fixed_prio = cma_c_false; \ 193 (tcb)->sched.class = cma__c_class_idle; \ 194 break; \ 195 } \ 196 default : { \ 197 cma__bugcheck ("cma__sched_parameterize: bad scheduling Policy"); \ 198 break; \ 199 } \ 200 } \ 201 } 202 203 /* 204 * TYPEDEFS 205 */ 206 207 /* 208 * Scheduling classes 209 */ 210 typedef enum CMA__T_SCHED_CLASS { 211 cma__c_class_rt, 212 cma__c_class_fore, 213 cma__c_class_back, 214 cma__c_class_idle 215 } cma__t_sched_class; 216 217 /* 218 * GLOBAL DATA 219 */ 220 221 /* 222 * Minimuma and maximum prioirities, for foreground and background threads, 223 * as of the last time the scheduler ran. (Scaled once.) 224 */ 225 extern cma_t_integer cma__g_prio_fg_min; 226 extern cma_t_integer cma__g_prio_fg_max; 227 extern cma_t_integer cma__g_prio_bg_min; 228 extern cma_t_integer cma__g_prio_bg_max; 229 230 /* 231 * The "m" values are the slopes of the four sections of linear approximation. 232 * 233 * cma__g_prio_m_I = 4*N(I)/cma__g_prio_range (Scaled once.) 234 */ 235 extern cma_t_integer cma__g_prio_m_0, 236 cma__g_prio_m_1, 237 cma__g_prio_m_2, 238 cma__g_prio_m_3; 239 240 /* 241 * The "b" values are the intercepts of the four sections of linear approx. 242 * (Not scaled.) 243 * 244 * cma__g_prio_b_I = -N(I)*(I*prio_max + (4-I)*prio_min)/prio_range + prio_o_I 245 */ 246 extern cma_t_integer cma__g_prio_b_0, 247 cma__g_prio_b_1, 248 cma__g_prio_b_2, 249 cma__g_prio_b_3; 250 251 /* 252 * The "p" values are the end points of the four sections of linear approx. 253 * 254 * cma__g_prio_p_I = cma__g_prio_fg_min + (I/4)*cma__g_prio_range 255 * 256 * [cma__g_prio_p_0 is not defined since it is not used (also, it is the same 257 * as cma__g_prio_fg_min).] (Scaled once.) 258 */ 259 extern cma_t_integer cma__g_prio_p_1, 260 cma__g_prio_p_2, 261 cma__g_prio_p_3; 262 263 /* 264 * Points to the next queue for the dispatcher to check for ready threads. 265 */ 266 extern cma_t_integer cma__g_next_ready_queue; 267 268 /* 269 * Points to the queues of virtual processors (for preempt victim search) 270 */ 271 extern cma__t_queue cma__g_run_vps; 272 extern cma__t_queue cma__g_susp_vps; 273 extern cma_t_integer cma__g_vp_count; 274 275 /* 276 * INTERNAL INTERFACES 277 */ 278 279 #endif 280