insights on reducing total cpu usage/realtime? in Developer Help

ID:764350
 
May 22 2012, 3:58 pm (Edited on May 22 2012, 4:45 pm)
(See the best response by Nadrew.)
Profile:
                                  Profile results (total time)
Proc Name                                        Self CPU    Total CPU    Real Time        Calls
--------------------------------------------    ---------    ---------    ---------    ---------
/mob/mobs/start                                  2836.503     2896.235    582370.563        21578
/mob/proc/mobcheck                                 33.849     2830.942    565216.563       532645
/client/proc/savegame                             145.881      496.566    48782.426        15704
/mob/Write                                        333.418      333.436      333.473        15703
/mob/Stat                                           7.362      134.555    521407.375       249926
/obj/projectile/Fire                               78.327      121.768    72620.891        31897
/mob/proc/updatestats                               1.779      103.227      103.305       229675
/client/Move                                       22.159      101.889      102.175       650676
/mob/proc/bullycheck                                0.078       98.561    17088.494         9797
/mob/proc/updatecompletestats                      89.838       90.216       90.319       186142
/mob/Move                                          73.695       85.811       86.211       873278


Problem description: The server uses too much CPU. I don't know any other means of reducing it, I have tried random fixes.

/mob/mobs/start: starts the AI
/mob/proc/mobcheck: checks surrounding mobs around you that aren't 'active'
/mob/proc/bullycheck: checks for a certain mob and starts it


Saving:
client/proc
    savegame()
        set background = 1
        var/savefile/f = new("players/[ckey].sav")
        if(mob)
            f["playername"] << mob.name
            f["mob"] << mob


AI:
mob/proc
    bullycheck(var/mob/m)
        set background = 1
        if(istype(m, /mob/mobs/Bully) && !m.active) spawn() m.start()

    mobcheck()
        set background = 1

        for(var/mob/mobs/m in viewers(7, src))
            if(!m || m.active && m.target != null || !see_invisible && m.invisibility || istype(m, /mob/mobs/Bully))
                continue

            m.target = src
            spawn() m.start()

mob
    start()
        set background = 1

        if(active || !target)
            return

        active = 1

        while(active && target != null && get_dist(src, target) <= 7)
            if(stamina >= maxstamina * 0.20)

                if(get_dist(src, target) == 1 && punchdelay <= world.time) attack(target)
                if(get_dist(src, target) >= 2) step_to(src, target)

            else

                step_away(src, target)

            sleep(4)
#1 May 22 2012, 4:02 pm
Looks like /mob/mobs/start() is taking up most of the resources, you should look into refining that function to be less intensive.
#2 May 22 2012, 4:04 pm
In response to Nadrew (#1)
Nadrew wrote:
Looks like /mob/mobs/start() is taking up most of the resources, you should look into refining that function to be less intensive.

I don't know the greatest way to write AI systems, I try to do with what I know. I have to have the mobs moving around obstacles, things like step_towards() doesn't do that.

EDIT: I updated the original post with the AI.
#3 May 22 2012, 4:06 pm
Best response
You should probably be leaving the AI inactive unless it needs to be active. Doing something like 'activating' the AI when a player comes within view of the NPC saves a lot of resources.
#4 May 22 2012, 4:40 pm
In response to Nadrew (#3)
Nadrew wrote:
You should probably be leaving the AI inactive unless it needs to be active. Doing something like 'activating' the AI when a player comes within view of the NPC saves a lot of resources.

mobcheck() is called on client/Move(), this is how an AI is activated. start() is the actual AI loop.
#5 May 22 2012, 4:46 pm
It appears that the start() loop isn't being allowed to finish; it looks like it should with the distance check but perhaps there's something else causing it to trigger needlessly.

Are you making sure NPC's can't cause the AI of other NPC's to activate?
#6 May 22 2012, 4:56 pm
In response to Nadrew (#5)
I could perhaps use (target in viewers(7, src)), but I heard that it uses more resoureces, and I doubt that the get_dist() doesn't work.

client
    Move()
        if(mob.movementdelay > world.time)
            return

        spawn() if(mob.level >= 20) mob.mobcheck()

        return ..()


It's built on client/Move(), so I presumed non-players couldn't active them.
#7 May 22 2012, 5:38 pm
BYOND's profiler doesn't make it easy to tell where the CPU time is spent. I'm pretty sure it includes calls to sleep towards the proc's self CPU time. The start() proc has a lot of CPU time because it hits the sleep() statement a lot, not because it's doing a lot of expensive computations.

As long as there's no way you're activating the mob's AI loop twice for the same mob, I don't see anything that'd be using up a lot of CPU time.
#8 May 26 2012, 8:36 am (Edited on May 26 2012, 9:28 am)
The problem is that step_to()/get_step_to()/walk_to (anything that deals with _to()) uses an insane amount of CPU usage. With 3 players and almost a full screen of active mobs, the CPU usage peaked over 100%.

This would freeze up the Linux server I am using, causing me to have to forcefully shutdown DreamDaemon through kill.

EDIT: With approximately 120 mobs, with world.cpu, it returned, on average, 100-130%. The server CPU was approximately 50-65%, on average. (only when the mobs are attempting to step_to() another mob)