Software Experiments with Fun & Inspiration

I decided to make some simple and temporal solution (but maybe permanent? :) )

In os/port/dis.c in vmachine() have static var indicates when GC was completed last time and start new routine of GC only when at least 500 msecs passed:

void
vmachine(void*)
{
        Prog *r;
        Osenv *o;
        int cycles;
        static ulong lastgcmsec =0;

        startup();

        while(waserror()) {
                if(up->type != Interp)
                        panic("vmachine: non-interp kproc");
                if(up->iprog != nil)
                        acquire();
                if(handler(up->env->errstr) == 0) {
                        propex(currun(), up->env->errstr);
                        progexit();
                }
                up->env = &up->defenv;
        }

        cycles = 0;
        for(;;) {
                if(tready(nil) == 0) {
                        ulong now = TK2MS(MACHP(0)->ticks);
                        if ((now - lastgcmsec) >500 /* || lowmem() */) {
                                strcpy(up->text, "gc");
                                execatidle();
                                lastgcmsec = TK2MS(MACHP(0)->ticks);
                        }
                        strcpy(up->text, "idle");
                        sleep(&isched.irend, tready, 0);
                        strcpy(up->text, "dis");

                }

                if(isched.vmq != nil && (isched.runhd == nil || ++cycles > 2)){
                        iyield();
                        cycles = 0;
                }

                r = isched.runhd;
                if(r != nil) {
                        o = r->osenv;
                        up->env = o;

                        FPrestore(&o->fpu);
                        r->xec(r);
                        FPsave(&o->fpu);

                        if(isched.runhd != nil)
                                if(r == isched.runhd)
                                        if(isched.runhd != isched.runtl) {
                                                isched.runhd = r->link;
                                                r->link = nil;
                                                isched.runtl->link = r;
                                                isched.runtl = r;
                                        }
                        up->env = &up->defenv;
                        if(isched.runhd != nil) {
                                ulong now = TK2MS(MACHP(0)->ticks);
                                if ((now - lastgcmsec) >500 /* || lowmem() */) {
                                        if (up->iprog == nil) {
                                                strcpy(up->text, "gc");
                                                up->type = BusyGC;
                                                pushrun(up->prog);
                                                rungc(isched.head);
                                                up->type = Interp;
                                                delrunq(up->prog);
                                                strcpy(up->text, "dis");
                                                lastgcmsec = TK2MS(MACHP(0)->ticks);
                                        } else
                                                print("up->iprog not nil (%lux)\n", up->iprog);
                                }
                        }
                }
        }
}

That made a trick!

; time math/sieve 1000000 >/dev/null
0.01l 3.13r 3.14t

(3.14 just because it is run on Pi :) )

What is amazing is performance, comparing some 3.3GHz old Core2:

Linux mur 4.1.6-hardened #3 SMP Sun Sep 27 11:44:36 CEST 2015 i686 Intel(R) Core(TM)2 Duo CPU E8600 @ 3.33GHz GenuineIntel GNU/Linux
alex@mur ~/work/pi/bb-inf-rpi/os/rpi $ emu
; time math/sieve 1000000 > /dev/null
0.014l 0.793r 0.807t

New release is coming soon! (let’s just have some little testing)