uvm_loadav: don't recompute schedstate_percpu.spc_nrun

We track the nrun value in schedstate_percpu.spc_nrun.  There is no
reason to walk the allproc list to recompute it.

Prompted by claudio@.

Thread: https://marc.info/?l=openbsd-tech&m=169059099426049&w=2

ok claudio@

diff --git a/sys/uvm/uvm_meter.c b/sys/uvm/uvm_meter.c
index 351b8a5..df58c31 100644 (file)
--- a/sys/uvm/uvm_meter.c
+++ b/sys/uvm/uvm_meter.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: uvm_meter.c,v 1.45 2023/08/01 14:15:44 claudio Exp $  */
+/*     $OpenBSD: uvm_meter.c,v 1.46 2023/08/02 13:54:45 cheloha Exp $  */
 /*     $NetBSD: uvm_meter.c,v 1.21 2001/07/14 06:36:03 matt Exp $      */
 
 /*
@@ -100,44 +100,30 @@ uvm_loadav(struct loadavg *avg)
 {
        CPU_INFO_ITERATOR cii;
        struct cpu_info *ci;
-       int i, nrun;
-       struct proc *p;
-       int nrun_cpu[MAXCPUS];
+       struct schedstate_percpu *spc;
+       u_int i, nrun = 0, nrun_cpu;
+       int s;
 
-       nrun = 0;
-       memset(nrun_cpu, 0, sizeof(nrun_cpu));
 
-       LIST_FOREACH(p, &allproc, p_list) {
-               switch (p->p_stat) {
-               case SSTOP:
-               case SSLEEP:
-                       break;
-               case SRUN:
-               case SONPROC:
-                       if (p == p->p_cpu->ci_schedstate.spc_idleproc)
-                               continue;
-               /* FALLTHROUGH */
-               case SIDL:
-                       nrun++;
-                       if (p->p_cpu)
-                               nrun_cpu[CPU_INFO_UNIT(p->p_cpu)]++;
-               }
+       SCHED_LOCK(s);
+       CPU_INFO_FOREACH(cii, ci) {
+               spc = &ci->ci_schedstate;
+               nrun_cpu = spc->spc_nrun;
+               if (ci->ci_curproc != spc->spc_idleproc)
+                       nrun_cpu++;
+               if (nrun_cpu == 0)
+                       continue;
+               spc->spc_ldavg = (cexp[0] * spc->spc_ldavg +
+                   nrun_cpu * FSCALE *
+                   (FSCALE - cexp[0])) >> FSHIFT;
+               nrun += nrun_cpu;
        }
+       SCHED_UNLOCK(s);
 
        for (i = 0; i < 3; i++) {
                avg->ldavg[i] = (cexp[i] * avg->ldavg[i] +
                    nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT;
        }
-
-       CPU_INFO_FOREACH(cii, ci) {
-               struct schedstate_percpu *spc = &ci->ci_schedstate;
-
-               if (nrun_cpu[CPU_INFO_UNIT(ci)] == 0)
-                       continue;
-               spc->spc_ldavg = (cexp[0] * spc->spc_ldavg +
-                   nrun_cpu[CPU_INFO_UNIT(ci)] * FSCALE *
-                   (FSCALE - cexp[0])) >> FSHIFT;
-       }
 }
 
 char malloc_conf[16];