Re: memory behavior to expect with gjdoc-0.7.6

[Robert Lougher]

Hi,

On 12/5/05, Mark Wielaard <address@hidden> wrote:
> Hi Fred,
>
> On Mon, 2005-12-05 at 12:32 -0500, address@hidden wrote:
> > > Could you also run JamVM with -verbose:gc and send me the output?
> > >
> > Attached.
>
> Thanks. This seems to point out two things:
>
> 1) There is a huge allocation (2MB+):
>   <GC: Alloc attempt for 2209016 bytes failed.>
>   at this point in the code:
>
>    // REVIEW: Using max instead of average may allocate a very large
>    // buffer.  Maybe we should do something more efficient?
>    int remaining = in.remaining ();
>    int n = (int) (remaining * maxBytesPerChar ());
>    ByteBuffer out = ByteBuffer.allocate (n);
>
>  I believe that REVIEW note gives us a hint :)
>
> 2) JamVM has fragmented its heap so much that it cannot allocate such a
>   block of data even though there is enough space in total:
>   <GC: Largest block is 2087448 total free is 778822576 out of
>    943718392 (82%)>
>
>   Or am I reading the output incorrectly?
>

This is what I was afraid of.  JamVM doesn't use handles so compaction
is a non-trivial exercise.  However, I'd like to analyse the gc output
myself, but I don't seem to have been sent it...

Rob.

> Cheers,
>
> Mark