1 /* kern_clock.c 4.21 81/04/28 */ 2 3 #include "../h/param.h" 4 #include "../h/systm.h" 5 #include "../h/dk.h" 6 #include "../h/callout.h" 7 #include "../h/seg.h" 8 #include "../h/dir.h" 9 #include "../h/user.h" 10 #include "../h/proc.h" 11 #include "../h/reg.h" 12 #include "../h/psl.h" 13 #include "../h/vm.h" 14 #include "../h/buf.h" 15 #include "../h/text.h" 16 #include "../h/vlimit.h" 17 #include "../h/mtpr.h" 18 #include "../h/clock.h" 19 #include "../h/cpu.h" 20 21 #include "bk.h" 22 #include "dh.h" 23 #include "dz.h" 24 25 /* 26 * Hardclock is called straight from 27 * the real time clock interrupt. 28 * We limit the work we do at real clock interrupt time to: 29 * reloading clock 30 * decrementing time to callouts 31 * recording cpu time usage 32 * modifying priority of current process 33 * arrange for soft clock interrupt 34 * kernel pc profiling 35 * 36 * At software (softclock) interrupt time we: 37 * implement callouts 38 * maintain date 39 * lightning bolt wakeup (every second) 40 * alarm clock signals 41 * jab the scheduler 42 * 43 * On the vax softclock interrupts are implemented by 44 * software interrupts. Note that we may have multiple softclock 45 * interrupts compressed into one (due to excessive interrupt load), 46 * but that hardclock interrupts should never be lost. 47 */ 48 49 /*ARGSUSED*/ 50 hardclock(pc, ps) 51 caddr_t pc; 52 { 53 register struct callout *p1; 54 register struct proc *pp; 55 register int s, cpstate; 56 57 /* 58 * reprime clock 59 */ 60 clkreld(); 61 62 /* 63 * update callout times 64 */ 65 for (p1 = calltodo.c_next; p1 && p1->c_time <= 0; p1 = p1->c_next) 66 ; 67 if (p1) 68 p1->c_time--; 69 70 /* 71 * Maintain iostat and per-process cpu statistics 72 */ 73 if (!noproc) { 74 s = u.u_procp->p_rssize; 75 u.u_vm.vm_idsrss += s; 76 if (u.u_procp->p_textp) { 77 register int xrss = u.u_procp->p_textp->x_rssize; 78 79 s += xrss; 80 u.u_vm.vm_ixrss += xrss; 81 } 82 if (s > u.u_vm.vm_maxrss) 83 u.u_vm.vm_maxrss = s; 84 if ((u.u_vm.vm_utime+u.u_vm.vm_stime+1)/hz > u.u_limit[LIM_CPU]) { 85 psignal(u.u_procp, SIGXCPU); 86 if (u.u_limit[LIM_CPU] < INFINITY - 5) 87 u.u_limit[LIM_CPU] += 5; 88 } 89 } 90 /* 91 * Update iostat information. 92 */ 93 if (USERMODE(ps)) { 94 u.u_vm.vm_utime++; 95 if(u.u_procp->p_nice > NZERO) 96 cpstate = CP_NICE; 97 else 98 cpstate = CP_USER; 99 } else { 100 cpstate = CP_SYS; 101 if (noproc) 102 cpstate = CP_IDLE; 103 else 104 u.u_vm.vm_stime++; 105 } 106 cp_time[cpstate]++; 107 for (s = 0; s < DK_NDRIVE; s++) 108 if (dk_busy&(1<<s)) 109 dk_time[s]++; 110 /* 111 * Adjust priority of current process. 112 */ 113 if (!noproc) { 114 pp = u.u_procp; 115 pp->p_cpticks++; 116 if(++pp->p_cpu == 0) 117 pp->p_cpu--; 118 if(pp->p_cpu % 16 == 0) { 119 (void) setpri(pp); 120 if (pp->p_pri >= PUSER) 121 pp->p_pri = pp->p_usrpri; 122 } 123 } 124 /* 125 * Time moves on. 126 */ 127 ++lbolt; 128 #if VAX780 129 /* 130 * On 780's, impelement a fast UBA watcher, 131 * to make sure uba's don't get stuck. 132 */ 133 if (cpu == VAX_780 && panicstr == 0 && !BASEPRI(ps)) 134 unhang(); 135 #endif 136 /* 137 * Schedule a software interrupt for the rest 138 * of clock activities. 139 */ 140 setsoftclock(); 141 } 142 143 /* 144 * SCHMAG is the constant in the digital decay cpu 145 * usage priority assignment. Each second we multiply 146 * the previous cpu usage estimate by SCHMAG. At 9/10 147 * it tends to decay away all knowledge of previous activity 148 * in about 10 seconds. 149 */ 150 #define SCHMAG 9/10 151 152 /* 153 * Constant for decay filter for cpu usage field 154 * in process table (used by ps au). 155 */ 156 double ccpu = 0.95122942450071400909; /* exp(-1/20) */ 157 158 /* 159 * Software clock interrupt. 160 * This routine runs at lower priority than device interrupts. 161 */ 162 /*ARGSUSED*/ 163 softclock(pc, ps) 164 caddr_t pc; 165 { 166 register struct callout *p1; 167 register struct proc *pp; 168 register int a, s; 169 caddr_t arg; 170 int (*func)(); 171 172 /* 173 * Perform callouts (but not after panic's!) 174 */ 175 if (panicstr == 0) { 176 for (;;) { 177 s = spl7(); 178 if ((p1 = calltodo.c_next) == 0 || p1->c_time > 0) 179 break; 180 calltodo.c_next = p1->c_next; 181 arg = p1->c_arg; 182 func = p1->c_func; 183 p1->c_next = callfree; 184 callfree = p1; 185 (void) splx(s); 186 (*func)(arg); 187 } 188 } 189 190 /* 191 * Drain silos. 192 */ 193 #if NBK > 0 194 #if NDH > 0 195 s = spl5(); dhtimer(); splx(s); 196 #endif 197 #if NDZ > 0 198 s = spl5(); dztimer(); splx(s); 199 #endif 200 #endif 201 202 /* 203 * If idling and processes are waiting to swap in, 204 * check on them. 205 */ 206 if (noproc && runin) { 207 runin = 0; 208 wakeup((caddr_t)&runin); 209 } 210 211 /* 212 * Run paging daemon and reschedule every 1/4 sec. 213 */ 214 if (lbolt % (hz/4) == 0) { 215 vmpago(); 216 runrun++; 217 aston(); 218 } 219 220 /* 221 * Lightning bolt every second: 222 * sleep timeouts 223 * process priority recomputation 224 * process %cpu averaging 225 * virtual memory metering 226 * kick swapper if processes want in 227 */ 228 if (lbolt >= hz) { 229 /* 230 * This doesn't mean much on VAX since we run at 231 * software interrupt time... if hardclock() 232 * calls softclock() directly, it prevents 233 * this code from running when the priority 234 * was raised when the clock interrupt occurred. 235 */ 236 if (BASEPRI(ps)) 237 return; 238 239 /* 240 * If we didn't run a few times because of 241 * long blockage at high ipl, we don't 242 * really want to run this code several times, 243 * so squish out all multiples of hz here. 244 */ 245 time += lbolt / hz; 246 lbolt %= hz; 247 248 /* 249 * Wakeup lightning bolt sleepers. 250 * Processes sleep on lbolt to wait 251 * for short amounts of time (e.g. 1 second). 252 */ 253 wakeup((caddr_t)&lbolt); 254 255 /* 256 * Recompute process priority and process 257 * sleep() system calls as well as internal 258 * sleeps with timeouts (tsleep() kernel routine). 259 */ 260 for (pp = proc; pp < procNPROC; pp++) 261 if (pp->p_stat && pp->p_stat!=SZOMB) { 262 /* 263 * Increase resident time, to max of 127 seconds 264 * (it is kept in a character.) For 265 * loaded processes this is time in core; for 266 * swapped processes, this is time on drum. 267 */ 268 if (pp->p_time != 127) 269 pp->p_time++; 270 /* 271 * If process has clock counting down, and it 272 * expires, set it running (if this is a tsleep()), 273 * or give it an SIGALRM (if the user process 274 * is using alarm signals. 275 */ 276 if (pp->p_clktim && --pp->p_clktim == 0) 277 if (pp->p_flag & STIMO) { 278 s = spl6(); 279 switch (pp->p_stat) { 280 281 case SSLEEP: 282 setrun(pp); 283 break; 284 285 case SSTOP: 286 unsleep(pp); 287 break; 288 } 289 pp->p_flag &= ~STIMO; 290 splx(s); 291 } else 292 psignal(pp, SIGALRM); 293 /* 294 * If process is blocked, increment computed 295 * time blocked. This is used in swap scheduling. 296 */ 297 if (pp->p_stat==SSLEEP || pp->p_stat==SSTOP) 298 if (pp->p_slptime != 127) 299 pp->p_slptime++; 300 /* 301 * Update digital filter estimation of process 302 * cpu utilization for loaded processes. 303 */ 304 if (pp->p_flag&SLOAD) 305 pp->p_pctcpu = ccpu * pp->p_pctcpu + 306 (1.0 - ccpu) * (pp->p_cpticks/(float)hz); 307 /* 308 * Recompute process priority. The number p_cpu 309 * is a weighted estimate of cpu time consumed. 310 * A process which consumes cpu time has this 311 * increase regularly. We here decrease it by 312 * a fraction (SCHMAG is 90%), giving a digital 313 * decay filter which damps out in about 10 seconds. 314 * 315 * If a process is niced, then the nice directly 316 * affects the new priority. The final priority 317 * is in the range 0 to 255, to fit in a character. 318 */ 319 pp->p_cpticks = 0; 320 a = (pp->p_cpu & 0377)*SCHMAG + pp->p_nice - NZERO; 321 if (a < 0) 322 a = 0; 323 if (a > 255) 324 a = 255; 325 pp->p_cpu = a; 326 (void) setpri(pp); 327 /* 328 * Now have computed new process priority 329 * in p->p_usrpri. Carefully change p->p_pri. 330 * A process is on a run queue associated with 331 * this priority, so we must block out process 332 * state changes during the transition. 333 */ 334 s = spl6(); 335 if (pp->p_pri >= PUSER) { 336 if ((pp != u.u_procp || noproc) && 337 pp->p_stat == SRUN && 338 (pp->p_flag & SLOAD) && 339 pp->p_pri != pp->p_usrpri) { 340 remrq(pp); 341 pp->p_pri = pp->p_usrpri; 342 setrq(pp); 343 } else 344 pp->p_pri = pp->p_usrpri; 345 } 346 splx(s); 347 } 348 349 /* 350 * Perform virtual memory metering. 351 */ 352 vmmeter(); 353 354 /* 355 * If the swap process is trying to bring 356 * a process in, have it look again to see 357 * if it is possible now. 358 */ 359 if (runin!=0) { 360 runin = 0; 361 wakeup((caddr_t)&runin); 362 } 363 364 /* 365 * If there are pages that have been cleaned, 366 * jolt the pageout daemon to process them. 367 * We do this here so that these pages will be 368 * freed if there is an abundance of memory and the 369 * daemon would not be awakened otherwise. 370 */ 371 if (bclnlist != NULL) 372 wakeup((caddr_t)&proc[2]); 373 374 /* 375 * If the trap occurred from usermode, 376 * then check to see if it has now been 377 * running more than 10 minutes of user time 378 * and should thus run with reduced priority 379 * to give other processes a chance. 380 */ 381 if (USERMODE(ps)) { 382 pp = u.u_procp; 383 if (pp->p_uid && pp->p_nice == NZERO && 384 u.u_vm.vm_utime > 600 * hz) 385 pp->p_nice = NZERO+4; 386 (void) setpri(pp); 387 pp->p_pri = pp->p_usrpri; 388 } 389 } 390 /* 391 * If trapped user-mode, give it a profiling tick. 392 */ 393 if (USERMODE(ps) && u.u_prof.pr_scale) { 394 u.u_procp->p_flag |= SOWEUPC; 395 aston(); 396 } 397 } 398 399 /* 400 * Timeout is called to arrange that 401 * fun(arg) is called in tim/hz seconds. 402 * An entry is linked into the callout 403 * structure. The time in each structure 404 * entry is the number of hz's more 405 * than the previous entry. 406 * In this way, decrementing the 407 * first entry has the effect of 408 * updating all entries. 409 * 410 * The panic is there because there is nothing 411 * intelligent to be done if an entry won't fit. 412 */ 413 timeout(fun, arg, tim) 414 int (*fun)(); 415 caddr_t arg; 416 { 417 register struct callout *p1, *p2, *pnew; 418 register int t; 419 int s; 420 421 /* DEBUGGING CODE */ 422 int ttrstrt(); 423 424 if (fun == ttrstrt && arg == 0) 425 panic("timeout ttrstr arg"); 426 /* END DEBUGGING CODE */ 427 t = tim; 428 s = spl7(); 429 pnew = callfree; 430 if (pnew == NULL) 431 panic("timeout table overflow"); 432 callfree = pnew->c_next; 433 pnew->c_arg = arg; 434 pnew->c_func = fun; 435 for (p1 = &calltodo; (p2 = p1->c_next) && p2->c_time < t; p1 = p2) 436 t -= p2->c_time; 437 p1->c_next = pnew; 438 pnew->c_next = p2; 439 pnew->c_time = t; 440 if (p2) 441 p2->c_time -= t; 442 splx(s); 443 } 444