Re: time to create / memory footprint of VM
- From: Tim Caswell <tim@xxxxxxxxxxxxxx>
- To: luajit@xxxxxxxxxxxxx
- Date: Sun, 15 Jul 2012 20:05:57 -0500
Mike, I didn't realize that coroutines were that cheap! How to they
compare to just using callbacks for everything like we do in
nodejs/luvit? I assume callbacks are cheaper, but I've been proved
wrong before.
On Sun, Jul 15, 2012 at 6:47 AM, Mike Pall <mike-1207@xxxxxxxxxx> wrote:
> Tobias Oberstein wrote:
>> Could someone give me a rough estimate on
>>
>> - time it takes to instantiate a new VM
>
> 2 microseconds for lua_open() (no libraries)
> 30 microseconds for lua_open() + luaL_newstate() (with all default libs)
>
> (On Linux/x64 at 3 GHz)
>
> You can cut down on the overhead if you don't need all libraries.
>
>> - the minimal memory footprint of a newly created VM instance
>
> 8 KB without any libraries
> 23 KB with all libraries
>
> That's the minimum footprint with a shared allocator across all
> instances (i.e. the system allocator, not the builtin one).
>
>> Say I have a process creating 10k VMs. How long will it take, how
>> much memory consume?
>
> That's not a useful scale for VM instances. Use one VM for each
> thread and divide them up with coroutines. Each coroutines needs
> only around 400 bytes, including a minimal stack.
>
> --Mike
>
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