new (more fifo) schedulint algorithm

newproc will reuse dead procs

SVN=127565

diff --git a/src/runtime/proc.c b/src/runtime/proc.c
index fee6255a1b830437dedc2167903f133a8895fa25..d6aed85f1c0a3b620d93824949fac6f9db9939e9 100644 (file)
--- a/src/runtime/proc.c
+++ b/src/runtime/proc.c
@@ -35,8 +35,24 @@ sys·newproc(int32 siz, byte* fn, byte* arg0)
                sys·panicl(123);
        }
 
-       newg = mal(sizeof(G));
-       stk = mal(4096);
+       // try to rip off an old goroutine
+       for(newg=allg; newg!=nil; newg=newg->alllink)
+               if(newg->status == Gdead)
+                       break;
+
+       if(newg == nil) {
+               newg = mal(sizeof(G));
+               stk = mal(4096);
+               newg->stack0 = stk;
+
+               newg->status = Gwaiting;
+               newg->alllink = allg;
+               allg = newg;
+       } else {
+               stk = newg->stack0;
+               newg->status = Gwaiting;
+       }
+
        newg->stackguard = stk+160;
 
        sp = stk + 4096 - 4*8;
@@ -56,8 +72,6 @@ sys·newproc(int32 siz, byte* fn, byte* arg0)
        newg->goid = goidgen;
 
        newg->status = Grunnable;
-       newg->alllink = allg;
-       allg = newg;
 
 //prints(" goid=");
 //sys·printint(newg->goid);
@@ -67,18 +81,25 @@ sys·newproc(int32 siz, byte* fn, byte* arg0)
 G*
 select(void)
 {
-       G *gp, *bestg;
+       G *gp;
 
-       bestg = nil;
+       gp = m->lastg;
+       if(gp == nil)
+               gp = allg;
+
+       for(gp=gp->alllink; gp!=nil; gp=gp->alllink) {
+               if(gp->status == Grunnable) {
+                       m->lastg = gp;
+                       return gp;
+               }
+       }
        for(gp=allg; gp!=nil; gp=gp->alllink) {
-               if(gp->status != Grunnable)
-                       continue;
-               if(bestg == nil || gp->pri < bestg->pri)
-                       bestg = gp;
+               if(gp->status == Grunnable) {
+                       m->lastg = gp;
+                       return gp;
+               }
        }
-       if(bestg != nil)
-               bestg->pri++;
-       return bestg;
+       return nil;
 }
 
 void

diff --git a/src/runtime/runtime.h b/src/runtime/runtime.h
index dec63eaa76a46404b4369caf241c1df48cb5b668..b1e8b69b259fb9c64c9f6451d683e56b242814ec 100644 (file)
--- a/src/runtime/runtime.h
+++ b/src/runtime/runtime.h
@@ -105,11 +105,11 @@ struct    G
 {
        byte*   stackguard;     // must not move
        byte*   stackbase;      // must not move
+       byte*   stack0;         // first stack segment
        Gobuf   sched;
        G*      alllink;        // on allq
        G*      qlink;          // on wait q
        int32   status;
-       int32   pri;
        int32   goid;
        byte    elem[8];        // transfer element for chan
 };
@@ -117,8 +117,9 @@ struct      M
 {
        G*      g0;             // g0 w interrupt stack - must not move
        uint64  morearg;        // arg to morestack - must not move
-       uint64  cret;   // return value from C - must not move
+       uint64  cret;           // return value from C - must not move
        G*      curg;           // current running goroutine
+       G*      lastg;          // last running goroutine - to emulate fifo
        Gobuf   sched;
        Gobuf   morestack;
        byte*   moresp;