/* clock.c 4.23 81/07/09 */ #include "../h/param.h" #include "../h/systm.h" #include "../h/dk.h" #include "../h/callout.h" #include "../h/seg.h" #include "../h/dir.h" #include "../h/user.h" #include "../h/proc.h" #include "../h/reg.h" #include "../h/psl.h" #include "../h/vm.h" #include "../h/buf.h" #include "../h/text.h" #include "../h/vlimit.h" #include "../h/mtpr.h" #include "../h/clock.h" #include "../h/cpu.h" #include "bk.h" #include "dh.h" #include "dz.h" /* * Hardclock is called straight from * the real time clock interrupt. * We limit the work we do at real clock interrupt time to: * reloading clock * decrementing time to callouts * recording cpu time usage * modifying priority of current process * arrange for soft clock interrupt * kernel pc profiling * * At software (softclock) interrupt time we: * implement callouts * maintain date * lightning bolt wakeup (every second) * alarm clock signals * jab the scheduler * * On the vax softclock interrupts are implemented by * software interrupts. Note that we may have multiple softclock * interrupts compressed into one (due to excessive interrupt load), * but that hardclock interrupts should never be lost. */ /*ARGSUSED*/ hardclock(pc, ps) caddr_t pc; { register struct callout *p1; register struct proc *pp; register int s, cpstate; /* * reprime clock */ clkreld(); /* * update callout times */ for (p1 = calltodo.c_next; p1 && p1->c_time <= 0; p1 = p1->c_next) ; if (p1) p1->c_time--; /* * Maintain iostat and per-process cpu statistics */ if (!noproc) { s = u.u_procp->p_rssize; u.u_vm.vm_idsrss += s; if (u.u_procp->p_textp) { register int xrss = u.u_procp->p_textp->x_rssize; s += xrss; u.u_vm.vm_ixrss += xrss; } if (s > u.u_vm.vm_maxrss) u.u_vm.vm_maxrss = s; if ((u.u_vm.vm_utime+u.u_vm.vm_stime+1)/hz > u.u_limit[LIM_CPU]) { psignal(u.u_procp, SIGXCPU); if (u.u_limit[LIM_CPU] < INFINITY - 5) u.u_limit[LIM_CPU] += 5; } } /* * Update iostat information. */ if (USERMODE(ps)) { u.u_vm.vm_utime++; if(u.u_procp->p_nice > NZERO) cpstate = CP_NICE; else cpstate = CP_USER; } else { cpstate = CP_SYS; if (noproc) cpstate = CP_IDLE; else u.u_vm.vm_stime++; } cp_time[cpstate]++; for (s = 0; s < DK_NDRIVE; s++) if (dk_busy&(1<<s)) dk_time[s]++; /* * Adjust priority of current process. */ if (!noproc) { pp = u.u_procp; pp->p_cpticks++; if(++pp->p_cpu == 0) pp->p_cpu--; if(pp->p_cpu % 4 == 0) { (void) setpri(pp); if (pp->p_pri >= PUSER) pp->p_pri = pp->p_usrpri; } } /* * Time moves on. */ ++lbolt; #if VAX780 /* * On 780's, impelement a fast UBA watcher, * to make sure uba's don't get stuck. */ if (cpu == VAX_780 && panicstr == 0 && !BASEPRI(ps)) unhang(); #endif /* * Schedule a software interrupt for the rest * of clock activities. */ setsoftclock(); } /* * The digital decay cpu usage priority assignment is scaled to run in * time as expanded by the 1 minute load average. Each second we * multiply the the previous cpu usage estimate by * nrscale*avenrun[0] * The following relates the load average to the period over which * cpu usage is 90% forgotten: * loadav 1 5 seconds * loadav 5 24 seconds * loadav 10 47 seconds * loadav 20 93 seconds * This is a great improvement on the previous algorithm which * decayed the priorities by a constant, and decayed away all knowledge * of previous activity in about 20 seconds. Under heavy load, * the previous algorithm degenerated to round-robin with poor response * time when there was a high load average. */ #undef ave #define ave(a,b) ((int)(((int)(a*b))/(b+1))) int nrscale = 2; double avenrun[]; /* * Constant for decay filter for cpu usage field * in process table (used by ps au). */ double ccpu = 0.95122942450071400909; /* exp(-1/20) */ /* * Software clock interrupt. * This routine runs at lower priority than device interrupts. */ /*ARGSUSED*/ softclock(pc, ps) caddr_t pc; { register struct callout *p1; register struct proc *pp; register int a, s; caddr_t arg; int (*func)(); /* * Perform callouts (but not after panic's!) */ if (panicstr == 0) { for (;;) { s = spl7(); if ((p1 = calltodo.c_next) == 0 || p1->c_time > 0) { splx(s); break; } calltodo.c_next = p1->c_next; arg = p1->c_arg; func = p1->c_func; p1->c_next = callfree; callfree = p1; (void) splx(s); (*func)(arg); } } /* * Drain silos. */ #if NBK > 0 #if NDH > 0 s = spl5(); dhtimer(); splx(s); #endif #if NDZ > 0 s = spl5(); dztimer(); splx(s); #endif #endif /* * If idling and processes are waiting to swap in, * check on them. */ if (noproc && runin) { runin = 0; wakeup((caddr_t)&runin); } /* * Run paging daemon every 1/4 sec. */ if (lbolt % (hz/4) == 0) { vmpago(); } /* * Reschedule every 1/10 sec. */ if (lbolt % (hz/10) == 0) { runrun++; aston(); } /* * Lightning bolt every second: * sleep timeouts * process priority recomputation * process %cpu averaging * virtual memory metering * kick swapper if processes want in */ if (lbolt >= hz) { /* * This doesn't mean much on VAX since we run at * software interrupt time... if hardclock() * calls softclock() directly, it prevents * this code from running when the priority * was raised when the clock interrupt occurred. */ if (BASEPRI(ps)) return; /* * If we didn't run a few times because of * long blockage at high ipl, we don't * really want to run this code several times, * so squish out all multiples of hz here. */ time += lbolt / hz; lbolt %= hz; /* * Wakeup lightning bolt sleepers. * Processes sleep on lbolt to wait * for short amounts of time (e.g. 1 second). */ wakeup((caddr_t)&lbolt); /* * Recompute process priority and process * sleep() system calls as well as internal * sleeps with timeouts (tsleep() kernel routine). */ for (pp = proc; pp < procNPROC; pp++) if (pp->p_stat && pp->p_stat!=SZOMB) { /* * Increase resident time, to max of 127 seconds * (it is kept in a character.) For * loaded processes this is time in core; for * swapped processes, this is time on drum. */ if (pp->p_time != 127) pp->p_time++; /* * If process has clock counting down, and it * expires, set it running (if this is a tsleep()), * or give it an SIGALRM (if the user process * is using alarm signals. */ if (pp->p_clktim && --pp->p_clktim == 0) if (pp->p_flag & STIMO) { s = spl6(); switch (pp->p_stat) { case SSLEEP: setrun(pp); break; case SSTOP: unsleep(pp); break; } pp->p_flag &= ~STIMO; splx(s); } else psignal(pp, SIGALRM); /* * If process is blocked, increment computed * time blocked. This is used in swap scheduling. */ if (pp->p_stat==SSLEEP || pp->p_stat==SSTOP) if (pp->p_slptime != 127) pp->p_slptime++; /* * Update digital filter estimation of process * cpu utilization for loaded processes. */ if (pp->p_flag&SLOAD) pp->p_pctcpu = ccpu * pp->p_pctcpu + (1.0 - ccpu) * (pp->p_cpticks/(float)hz); /* * Recompute process priority. The number p_cpu * is a weighted estimate of cpu time consumed. * A process which consumes cpu time has this * increase regularly. We here decrease it by * a fraction based on load average giving a digital * decay filter which damps out in about 5 seconds * when seconds are measured in time expanded by the * load average. * * If a process is niced, then the nice directly * affects the new priority. The final priority * is in the range 0 to 255, to fit in a character. */ pp->p_cpticks = 0; a = ave((pp->p_cpu & 0377), avenrun[0]*nrscale) + pp->p_nice - NZERO; if (a < 0) a = 0; if (a > 255) a = 255; pp->p_cpu = a; (void) setpri(pp); /* * Now have computed new process priority * in p->p_usrpri. Carefully change p->p_pri. * A process is on a run queue associated with * this priority, so we must block out process * state changes during the transition. */ s = spl6(); if (pp->p_pri >= PUSER) { if ((pp != u.u_procp || noproc) && pp->p_stat == SRUN && (pp->p_flag & SLOAD) && pp->p_pri != pp->p_usrpri) { remrq(pp); pp->p_pri = pp->p_usrpri; setrq(pp); } else pp->p_pri = pp->p_usrpri; } splx(s); } /* * Perform virtual memory metering. */ vmmeter(); /* * If the swap process is trying to bring * a process in, have it look again to see * if it is possible now. */ if (runin!=0) { runin = 0; wakeup((caddr_t)&runin); } /* * If there are pages that have been cleaned, * jolt the pageout daemon to process them. * We do this here so that these pages will be * freed if there is an abundance of memory and the * daemon would not be awakened otherwise. */ if (bclnlist != NULL) wakeup((caddr_t)&proc[2]); /* * If the trap occurred from usermode, * then check to see if it has now been * running more than 10 minutes of user time * and should thus run with reduced priority * to give other processes a chance. */ if (USERMODE(ps)) { pp = u.u_procp; if (pp->p_uid && pp->p_nice == NZERO && u.u_vm.vm_utime > 600 * hz) pp->p_nice = NZERO+4; (void) setpri(pp); pp->p_pri = pp->p_usrpri; } } /* * If trapped user-mode, give it a profiling tick. */ if (USERMODE(ps) && u.u_prof.pr_scale) { u.u_procp->p_flag |= SOWEUPC; aston(); } } /* * Timeout is called to arrange that * fun(arg) is called in tim/hz seconds. * An entry is linked into the callout * structure. The time in each structure * entry is the number of hz's more * than the previous entry. * In this way, decrementing the * first entry has the effect of * updating all entries. * * The panic is there because there is nothing * intelligent to be done if an entry won't fit. */ timeout(fun, arg, tim) int (*fun)(); caddr_t arg; { register struct callout *p1, *p2, *pnew; register int t; int s; /* DEBUGGING CODE */ int ttrstrt(); if (fun == ttrstrt && arg == 0) panic("timeout ttrstr arg"); /* END DEBUGGING CODE */ t = tim; s = spl7(); pnew = callfree; if (pnew == NULL) panic("timeout table overflow"); callfree = pnew->c_next; pnew->c_arg = arg; pnew->c_func = fun; for (p1 = &calltodo; (p2 = p1->c_next) && p2->c_time < t; p1 = p2) t -= p2->c_time; p1->c_next = pnew; pnew->c_next = p2; pnew->c_time = t; if (p2) p2->c_time -= t; splx(s); }