Re: How to kill slave kernel securely?
- To: mathgroup at smc.vnet.net
- Subject: [mg117519] Re: How to kill slave kernel securely?
- From: Daniel Lichtblau <danl at wolfram.com>
- Date: Mon, 21 Mar 2011 06:17:10 -0500 (EST)
----- Original Message -----
> From: "Alexey Popkov" <lehin.p at gmail.com>
> To: mathgroup at smc.vnet.net
> Sent: Saturday, March 19, 2011 5:22:07 AM
> Subject: [mg117474] Re: How to kill slave kernel securely?
> Oliver Ruebenkoenig <ruebenko at wolfram.com> wrote:
> > On Thu, 10 Mar 2011, Alexey Popkov wrote:
> > > 2) My bitter experience with MemoryConstrained clearly shows that
> > > it is
> not
> > > a reliable function. It practical cases when I heavily use such
> functions as
> > > NDSolve, NIntegrate etc. it often allows MathKernel to take for
> > > example
> > > 500-900 MB more that I have set. And system goes into swapping...
> >
> > You could forward that to the tech support for us to look at.
> >
> > Oliver
>
> I have found today a simple example when MemoryConstrained fails:
>
> In[1]:= MaxMemoryUsed[]
> MemoryConstrained[
> Quiet@Module[{f, n = 0},
> f[x_] := f[x + 1] + Plus @@ Table[Random[], {10^7}];
> Block[{$RecursionLimit = 3000}, f[0]]];, 90000000];
> MaxMemoryUsed[]
>
> Out[1]= 10757752
>
> Out[3]= 291258232
>
> You can see that MathKernel takes more than 260 Mb additional memory
> in peak
> although only less than 90 Mb additional memory was allowed by
> MemoryConstrained. This behavior is machine-dependent. Try to play
> with the
> memory constrain if you cannot reproduce.
>
> As I said before, my experience shows that in practice the overshoot
> can be
> 900 Mb and more! This often happens in complicated computations with
> heavy
> usage such functions as NDSolve and NIntegrate inside loops.
>
> Alexey
That MemoryConstrained returns $Aborted. What exactly do you mean by the claim that it fails? That it does not also account for subroutine stack space/ I believe that was already explained.
Daniel Lichtblau
Wolfram Research